Why all the fuss ?
All of this doesn't make much sense to me. The business world already has standardized on a distribution. Most places run RedHat because a proper contract makes the PHBs feel good, whether it's useful or not. Other distributions are only used when the admins have their say (doesn't happen that often in non tech places) or in smaller shops.
And even if CentOS vanished tomorrow, DimeOS would take over in a couple weeks. Its users probably wouldn't even have time to be impacted.
And re. the Mac, an awful lot of the people who have tried OS X (myself included) quickly came back to Linux / Unix. That horrible mess with its mangled filesystem, numerous quirks and poor i18n was just as bad as Windows to me. Unless you needed an application that ran in it, few people I know stuck with Apple's system, especially given their tendency to not be very open (and the pain of dealing with their users).
I know my iBook has been a doorstop for two years now, replaced it with a random Samsung PC that works just as well, doesn't always require an external mouse (X11 with 1 button is just too painful) and runs a KDE desktop just fine.
And now I can easily type all of the Latin-9 charset without looking up a table, in a logical way, and I have a lazy mouse focus which does *not* pop windows to the front. All of which are among the minimum essentials I expect from any current machine (Windows doesn't deliver either in that area : you *still* can't reliably type in French in Windows).
MacOS certainly isn't the best thing out there unless you set your requirements pretty low. It's better than Windows XP but that's not saying much.