Let me repeat that: OS X is not Unix.
Consider the following: all of Apple.com's marketing pages on the subject of their darling new operating system are extremely careful to note that OS X is "UNIX-based". While the foundation of the operating system is Darwin, a BSD-based kernel, the core of the operating system is NeXT; just ask all the hardcore Unix users who have tried to change their OS X settings using configuration files in /etc, only to find all their changes ignored. Apple's Unix-like operating system uses NetInfo, for a configuration datastore, something more akin to the Windows registry we all know and hate.
Consider, too, that any Unix users poking around an OS X box will be surprised to find a "Unix" with no gcc. Or gdb. Original versions didn't even have bash. And Unix's beloved fortune, who dutifully greets us upon login, is missing. That's because all of those utilities that arguably make a "Unix system" a Unix system don't come by default with OS X; users who care about these tools will need to find the Developer's Tools CD, which Apple is nice enough to ship with OS X, but which is not part of the operating system distribution. At least "Terminal.app", featuring "vt100/vt220 emulation on par with xterm", is there.
Speaking of xterm, where is X? You know, that often-maligned client/server hardware-independent platform MIT came up with to provide GUI services for *nix while Steve was still getting his Xerox knockoff right so Bill had something to steal? You won't find it in OS X by default. "Display PDF" provides the pretty pictures for OS X users to drool over, but if you need to run that X application, you have to find yourself an X server for Mac OS X, which Apple doesn't even want to acknowledge exists (but thanks to the XDarwin project, OS X users have something to run Unix programs on their "Unix" boxes).
I could go on with stories about Unix users who expected OS X to live up to the marketing hype (my favorite being that you have to "enable" the root user before you can login as root... "Unix" indeed) and were unpleasantly surprised.
To be clear: It's not that being a Unix-based operating system is bad. In fact, most OS X users will point out that my operating system of choice, Linux, isn't really Unix either, and they're right. But while the kernel is merely Unix-like, show me a Linux distribution that doesn't ship gcc, gdb, X, and all those other utilities (even fortune) that make Unix Unix.
Further, show me a Linux distribution that ignores /etc and stores its configuration data in a binary registry. Linux may not be Unix, but it is so rooted in a Unix heritage that it is in a position to offer its users a "Unix" desktop environment. Contrast this to OS X, which, for all of its praises, can never provide a "desktop environment for Unix". You can't give your users something you don't have.
Another weakness inherent in O'Reilly's argument that OS X is the future of desktop Unix reveals itself in his painstaking coverage of those who switched to OS X. If we were to believe his analysis, the KDE devs might as well all go get "real" jobs, since users are moving "in droves" to OS X for their desktop experience. A closer look at their stories betrays their motives, which reveal that they weren't using Linux for the right reasons and never really "grokked" the platform.
Putting aside those who upgraded from < OS X and those who migrated from Windows (we all know why they switched), the complaints of those who moved to OS X from Unix/Linux seem to fall into two categories: "User experience" on the Linux desktop isn't "there" and application support isn't always available for Unix/Linux.
Let's look at applications first. We all buy computers to get work done, and applications are the vehicle for accomplishing this. The two most popular applications you hear Mac OS X users raving about "just working" on their Macintosh come from the same company that Apple tried to go head to head with... and, like so many others, failed miserably. Unlike those now non-existent companies, Apple realized it before Microsoft cut off their air supply and went crying back to the monopolist like a dog with its tail between its legs to get Office.X and Internet Explorer ported so OS X didn't go the way of OS/2.
There is a special irony in the fact that these OS X users would support and, in some cases, highly praise a vendor they supposedly dislike so much for everything from technical to philosophical reasons. It suggests that OS X users switching from Unix on the desktop should never have switched to Unix on their desktops in the first place; you don't exactly switch to Linux for application support. Would they blame Wolfgang Puck for his sub-par cooking skills if they went to his restaurant looking for a gourmet Chinese dinner? The same invalid blame is placed when they fault Linux for their disappointment in what they perceive as a sub-par desktop experience when they were expecting clones of their Windows or OS 9 experiences.
The second category lies in the nebulous "user experience" realm. O'Reilly's testimonials include phrases like "[OS X] just works" or "Computing is fun again" or "[OS X] doesn't suck". Looking past loaded words, they don't mean anything. My Linux box, with its AfterStep desktop "just works". I've only recently begun to appreciate how fun and cool my Linux workstation is when I'm running gaim and Mozilla off my desktop at home, bounced through Solaris and HP-UX servers to a lab on campus. iTunes isn't "fun". That's fun, and it "just works".
A few of O'Reilly's testimonies do give some concrete examples of user problems they had: "I refuse to spend weekends and late nights fiddling, Linux-hacker-style, with the scripts and codes and config files...". This sentiment reinforces that these users shouldn't have been using Linux in the first place. Like most long time-Linux users, I know the pain of spending what seems like endless "cycles" trying to figure something out. But unlike other operating systems, once I hack those "scripts and codes and config files", it all "just works", and it continues to "just work" until I introduce a new variable into the equation. This is different from other desktop operating systems, OS X included, under which an application modifying something somewhere in some binary NetInfo registry could break something else. In other words, all that fiddling time may be annoying, but it is not for naught. Linux is very much a "configure once, run forever" operating system.
One of the "switchers" O'Reilly profiles likens the Linux desktop to a "typical British sports car from the 70s: Lots of engine, but it has a lousy paint job. The car 'mostly' runs, but the electrical system is erratic", while OS X is a "Mazda Miata: Stylish [and] sexy...". But Linux was never meant to be a sports car; I like to think of my Linux desktop more as an expandable VW bus towing a boat behind it and an SUV behind that. You don't really have the urge to "lick" it, but it does make you say "Damn... that's pretty cool", and you still have room for twenty more people and another car behind the SUV. See how far you get in your Miata when you try to stuff five people in it and attach a boat.
The final clue that O'Reilly's users shouldn't have been using Linux for their desktops is not what they said, but what they didn't say. Not one ex-Linux OS X user mentioned anything about freedom. I'm not referring to some Stallmanesque argument about whether the "GNU" goes before, after, or behind the "Linux", but rather my ability to look at the source code and find out exactly what it's doing if I need to, from the kernel on up. (Before OS X users mention the "Open Source" Darwin kernel, show me the source to Display PDF.) I can verify that applications aren't sending information off to Apple (or Microsoft). I can work and play on my Linux desktop without ever fearing that Linus will send me a cease and desist order for making my desktop look a certain way or telling the truth. And because my platform isn't controlled by a public corporation, I know that Linus won't slip some nefarious clause into a EULA because a majority of stockholders thinks it will maximize their profits. OS X users make a huge deal out of their beautiful, lickable desktop "just working", but the cost of this "convenience" is their freedom, both in terms of liberty and technical flexibility. For many Linux users, that's too high a price.
A "desktop environment" is many different things to different users of different platforms. It is unfair and invalid for current OS X users to fault the Linux desktop for shortcomings they perceived as they mistook a 747 for a (admittedly stylish, but smaller) Leer jet. The development of a "desktop environment" on Linux, in the form of KDE, Gnome, and -- in the tradition of Open Source -- software we haven't heard of yet, will continue and is of value to those who are using the Linux platform for the right reasons in the first place.
O'Reilly is wrong about Apple's possible markets. Apple may have a market in desktop users who want some of the stability and flexibility a Unix-based operating system affords them. They may even have a market in Unix users who want a desktop-focused platform for their home or desk at work, but they will never find one in Unix/Linux users who want a desktop environment.
Thanks Tim, but we already have a number of pretty damn good ones.