Ha ha! you all miss the point, surely?
First off, I'm no IT professional, I'm a research scientist. I know little about what *makes* an operating system. Like many of you I am sure, I learned BASIC on a ZX and a Speccy, then a 386 then did some C stuff at night school, so not a total dimmock, just an educated amateur. I use Mac's sometimes at conferences as they are reliable and don't crash half-way through a talk. I installed Linux once, but it didn't do much, and as I had no particular interest in half-finished home-written software to run on it, or hacking servers, and I am not a particularly skilled software developer, I uninstalled it.
What REALLY drives micro$oft's monopoly? Simple, 2 things, GAMES and MICROSOFT OFFICE.
Office is the global standard for business and it is a slow, difficult and expensive thing for a business to change. The only thing that would even begin a global change in business OS use would be to implement cross compatibility across all file types (which would surely restrict competitiveness and the development of new business software innovation), or a drastic reduction in the cost of a Mac (I can buy a Dell workstation for a couple of hundred quid VAT free through the University where I work).
For the common home user, (almost everybody) even those who primarily bought their box to edit photographs, or home movies and not to play games, many of them have kids (or husbands) who want games or easily available educational software. Not many contemporary games are available for the Mac (although this is changing a little), and I can't see kids getting much cred from bringing their mates home to play "Snake" on the family Linux system.
Yes, I am a gamer, but I also use Windows PCs to drive confocal microscopes and qPCR machines as well as for DTP, molecular biology and office apps in my office, so I am hardly an ignorant fanboy. Until the price of Macs comes down and general availability of Mac software increases, I'll have to stick to Windows PCs for my work and gaming, Linux remains a platform for the niche enthusiast or simple and cheap legacy user. Like me, the vast majority of users are not IT professionals, and until you all develop the ability to see past your own front yard, you'll never realize the big picture.