Unlikely, what you're referring to is the resistance of companies like Microsoft/Sony/Nintendo etc... to allow such software to exist and be continuously updated.  Microsoft/Sony/Nintendo would absolutely be able to make an emulation tool for 360/PS3/Wii, and you'd be able to run it windowed, while multi-tasking in the background.

Do not confuse the capability, with companies protecting their investment.

nah I don't confuse anything, but you might have forgotten that even the current preview of the emulator on X1 has problems running the games at their designed framerate and will probably never achieve a true 1:1.
Software emulation needs a lot of power, especially CPU power and since both PS3 and 360 had a very competent and complex CPU architecture that's no easy task.

That's a long long way away.

I never said it was easy, but it's most certainly doable (obviously, since Microsoft's actually doing it on the X1), and given both the X1 and PS4's CPU's aren't what you'd call 'power houses' (There were and continue to be better CPU's than what was chosen for the PS4/X1's architecture), it's fairly obvious modern PC's could easily do it (not the coding, the actual task), what w/ their massive RAM and GPU advantages.

Which ones? If there is an official PC-version (Halo 1 + 2, Gears of War 1, Fable 1 + 3, Dead Rising 3, Alan Wake...), it's no "xbox exclusive".

I find out funny how so many people that are not fans of Xbox, are critical of MS's decision to release more games on PC. Wonder why that is :).

why are americans buying this system should be rather the question

so the PS3 is even more consumer friendly than both alternatives?

I wouldn't even care that much about the exclusives.

Red Dead Redemption, Vanquish, MGS HD Collection (MGS 3 wasn't on PC) and Soul Calibur 4/5 would be more interesting.

Very true, but so is the way until MSoft does it.

The question is who will do it first, and I don't think it will be MSoft.