I had my first computer in 1978 so you having desktop PC's since the 90's is not exactly a big wow to me.
Yep, you are a typical Windows gaming guy and are only thinking in terms of Desktop. Linux "desktop" is just as powerful as Linux "server" because they are the same thing and scale beyond Enterprise all the way to the Top500 supercomputer list. Games do run better on Linux as you would know if you had tried it - hey at least it is very unlikely to crash on Linux or be infected with malware.
Linux can utilise nVidia, ATI and anyone else's proprietary drivers so what are talking about?
Microsoft would gain a lot by doing this because their product range would be built on top of solid foundations instead of the shit that it is built on now.
You have to understand that Microsoft are failing in the Server market with their operating system - it is a fact! And this means that the technology that transfers from the server development team is diminishing.
Don't be scared of Linux - it is SO much better than Windows and one day you will see that.