I live in a 3rd world country called Argentine.
Except medium-high and high class people have more need for food and clothes than computers.
Some people knows nothing about computers and os.. Some of them thinks that Windows is free, comes with a pc and there is no other choice.
Computer hardware is extra-cheap and generic. The majority of pcs sold here have mothers like PcChips or similar.
Almost no-one have more than one pc at their home (if they have at least one!) and the uses are game.. game... game.. internet (msn, mail and emule only) and maybe some scholar work.
Unless you are curious and a kind of "power user" there's on way to introduce Linux for easier the installations could be. People DO NOT WANT TO THINK !
With New Linux distros (I am using Ubuntu) drivers it's not a issue anymore. In fact, I have more hardware recognized and working out of the box with Linux than Windows XP, where I had to look for generics drivers for me tv-tunner, and my agfa scanner simply won't work with WinXP because it is "obsolete" (but fulfills my needs and have no money to buy another). (in fact I got two old tv-tunners as "gifts" because they won't work in winXP but I found Linux drivers)
But.. this is mi expertise. Reality is, argentinian's pcs are far more generics than mine and there's no support for winmodems nor some nics nor the usb adls-modem that telephone company distributes here. (and a router is out of budget)
As far as I know there's no support for such usbmodems in Linux and without internet people can not live... here Windows is "free"... so.. with windows I can have internet and Doom3 and HL2 then, Windows is the only choice. (besides the fact that most people do not know that there's a choice called Linux)
As they don't actually know how to use a windows pc, I spend most of my free time removing spyware, viruses, etc from friends pcs.
Another reason against Linux.. they won't install cedega (because every install in Linux makes you think) and even with cedega not every new game will work so.. If my HalfLife2 And Civilization4 doesn't work there's no use for my pc.
Similar happens with office applications. They do not want the OpenOffice.org spreadsheet, they want EXCEL.
As a semi-reasonable person, I think that windows, if used right, is secure and stable enough for home users, but it is not used like that (if I do everything as root in Linux, it will crack too, for example). If I don't give him Admin access to windows, will have complains about not being able to install the latest fancy game.
If, in countries like mine, legal software laws were applied rigourously then I have no doubt that Linux should be the number 1 operation system for home use.. simply because not even half of the people will have money to buy licenses of everything and if they could buy a Windows Licence for the Home Edition of XP (the most common here is Professional) they won't be able to buy neither Office, Photoshop, nor games.
If they were forced to use free software except for the OS. Free software which is available in Linux too, then would be no reason to not use Linux at all.
But as i said, a short mind and a sohrt budget make buy cheap hardware, cheap new hardware is bad supported for windows.. and worst for Linux (old cheap is a little better on Linux), the use of a pc is gaming and leisure, the less you think the better, everything is free, everybody "knows" windows... windows is the only winner and the only candidate.
Except at my university where made us use Linux and there's some geeks that thinks that the life is meaningless without Vim I know NOBODY who uses other OS than Windows.
But then again.. it is here, where TFT monitors are a dream, SLI is a weird idea and all software is free.
Sorry about my English.. As I said I am argentinian and speaks Spanish.