Xero- apologies for "fanatic", but I do think you took the first post a bit more seriously than I intended.
Posters in this thread are a self-selected minority- people interested in OSii by definition. My "type 2".
In the wider world, most home PC owners simply don't care what OS their machine runs, so long as it lets them do what they want, which in the main, is play media of various kinds, store files , browse the web and send email.
Linux will do all that just fine, but so will Windows, which was probably preinstalled when they bought the machine. For that huge majority of home users, there is no incentive whatever to change to Linux- not even cost, because the PC already came with Windows.
Same holds in the majority of work situations-Companies buy what will do the job. The job is generally data shuffling and communication. Windows does that fine and comes cheap if you are bulk buying machines and licences. Retraining costs money. Why bulk install a free OS if you then have to retrain your workforce?
OK , go with Ubuntu. Easy install. Free office suite. Shiny GUI. What's not to like?
Nothing. But you already got all that when you bought the machine - and in a form your staff are all familiar with. And it will run that old Portuguese laser printer in the basement,the one nobody ever heard of, that hasn't needed a toner replacement since 1990 and we don't want to lose it. Sure , there might be a Linux driver, but...
There's one big exception to all this - and it tends to involve the sort of people posting in this thread.
People who work on rather than with computer systems have a different perspective, whether they do so for a living, or for fun. It would surprise the users of most Windows PCs in an office to learn that the network server they use daily is probably a Linux box. It won't surprise anyone in the IT department.
If you are building a computer at home, sure use Linux, why not? The price is right.
But until it comes as a regular free option with prebuilt machines it is doomed to remain a minority choice.
Most home users don't need Linux and are unlikely to make any major gains by using it. Yes, security is better, but anyone savvy enough to be using Linux is apt to have Windows security sewn up tightly as well. Just running Ubuntu doesn't guarantee a routine user is safe from malware- and if it becomes more popular, the risk will increase disproportionately, because the sort of person who targets a virus at a Unix derived system is apt to be far better informed than the average Micro$oft script kid.
My history with computers started with a Sinclair ZX 80, back in the late Pleistocene. My first 4 computers- a ZX80, ZX81,QL and an HP85 all predated DOS, never mind Windows. (DOS 5.1 remains my favourite OS. GUI's I can live without.) But who in his right mind would want to run DOS now, even were the hardware strictly compatible? Yes it's small and neat (An OS on a single 1.44MB floppy, remember?)- but that's hardly an advantage if you have 4GB of RAM and a 1TB hard disc. (Oh those old 640K limit days...bliss was it in that dawn, to be young).
So why do I use Linux if I'm so negative about it? Well, I'm not negative about it. I like it fine. I just don't see that it offers me any gains worth the trouble on most modern PCs. I use it because of the hardware limits of an Asus 901, which came with (a different distro of) Linux preloaded. Because I tried XP on it and it ran like a 2 legged dog. I like it fine, but it's not needed on my home PC and so I stick with Windows. (I did dual boot for a while, but found no gain from it. Ever tried UN-installing Ubuntu? It's a pain. And I suppose that's an illustration of what I meant by "fanatic"; there's loads of help installing Linux these days, but finding out how to uninstall it is harder. It doesn't occur to the advocates that anyone might want to.
And that's not a friendly attitude.
In any case, it seems to me all computer OS advocates are in danger of going the way of the stegosaurus. Smartphones are where the action is. The big seller of 2011, hardware wise, is the iPad, which doesn't use either Windows or Linux. It uses IOS - and the competition is all running Android. Smartphone operating systems. It's 1981 all over again- Motorola V Intel, DOS v Apple OS.
It really seems to me this is the next revolution on a par with the IBM / Microsoft deal that produced the IBM PC, killed every other competitor but Apple and set the DOS/Windows standard OS environment for the last thirty years.
Sometimes, looking back on this, I feel very old.