Good. Let them.
Let Micro$oft come.
If they move to a Unix core, then the WHOLE world (ok most of it) is Unix. They who arn't Unix will smell enuf like Unix that we'll just call them Unix. (or how about unix)
If they pick FreeBSD, this means they have to explain why THEIR products are:
1) Better than 'reference BSD' (a battle you will get to watch Apple fight first)
2) Why their products do NOT work with 'reference BSD'.
3) How come NT isn't a "Better Unix than Unix".
4) How come thier version has a broken (insert name of whatever they have broken)
So let them come. The great satan will STILL be the great satan, just like the minor satan (apple) is still the minor satan...and we've welcomed them. Apple has contributed back bug fixes, so they are 'welcomed'. Just because they are in the tent DOES NOT mean we have to socialize with them. Like any ESTABLISHED social group, they have to conform to OUR norms to be accepted by US as a partner.
For me, it just means my skills as a Unix guru (as opposed to a Guru or GURU) are employable EVERYWHERE.