but right off the top of my head I can think of a person who uses a mac, linux only. Linus Torvalds. It'd be plain stupidity to think he's the only one. Yellow Dog Linux. Quite popular. It'll even run an XServe faster than OS X. OTOH, don't forget that probably most current Linux uses are for servers, not desktops. Linux is definitely ahead of Apple in servers.
Linux also has an infinitesimally small marketshare of joe user, much higher only in the geek world.
Linux also has an infinitesimally small marketshare of joe user, much higher only in the geek world.
There's more geeks out there than you think. And besides, don't forget those who are just anti microsoft to be anti microsoft therefore will use anything else.
Linux may require more work to learn out of the gate but by no means is today's distros hard/impossible. For someone who is genuinely motivated it'd be very easy to pickup.