The way I see it, linux will always be, and will always be available in a free form. It might be possible that certain linux-versions won't be free anymore(that's already a bit so right now..), but linux itselfs will always be free.
I also think that the Gui's like KDE will continiue to get better, and eventually it will be possible to use linux without knowing you are actually using linux. You will not need to know all this complicated stuff, it will be as easy as windows, only better...
Still for the 'power-users' the system will remain as open as it is now, and you will still have the full control.
on another matter, about windows your'e absolutely right, it won't give you full control, but I think MacOS X is getting quite far whit that. At least as far as a company which needs to make money whit his software can go.(making it 'open source' would be the next step, but i think making money whit that is getting a bit hard.. just my idea, don't know s*** about companys and making money
I hope Linux can get as userfrendly as MacOS X is. normal mac users don't even know the are using unix, if you don't tell them.