When Nintendo and/or Sony?

They sell their own systems, so not bloody likely. Nintendo doesn't even do PC work.

Well they have exclusivity

Why would they do that? They have their own platforms.

Sony has some of heir games on Steam, PlanetSide 2 and the Everquest MMOs for example.
Maybe that's it.

Its unlikely any of them would put out their exclusives on PC so long as they still make consoles, and its unlikely either of them will give up making consoles unless they had quite a few years of poor retail performance. So, I'd say no sooner than 10 years, if ever.

When the emulators come out.

Final Fantasy 7 and 8 were for Playstation 1. I cannot wait for a cooking mama game to go on steam xP

Sony is already doing it. I don't think Nintendo will ever follow suit. Only when consoles die out/get replaced by "smart" devices Nintendo has to go multiplatform.

I only play on the PC these days but I sure miss some great Nintendo games that I played on the SNES/N64/GC.

I could see games made for the PC/Android/iOS based off of their best selling franchises, but I can't see Nintendo actually migrating unless their systems go under like Sega did. With Nintendo's status as a major player - if not the player - in the gaming industry this is highly unlikely.

Nintendo probably in around 200 years

Use emulators if you want to play classic Nintendo or Sony games.

Sony is more interested in the PC than Nintendo. Evidence of this is the fact that the specs of the PS4 are similar to that of a PC. (Basically a PC in a nice, slim box.)

Nintendo wants you to buy their consoles and probably will not port their games to PC until they end up like Sega and stop making consoles.

Nintendo can crap in a bag, sell it as a mario statue and come out on top financially.

Thats one company that will not die or have a need to do this, sony is pretty well off also....