Nintendo, didnt they release a new ip on Wii that sold 80 million?

Only counts as a new IP if it's marketed towars us super serial gamers.

Which company would make "better" exclusives is quite debatable, and very subjective based on a person's preferences for what they want in a game. Which company would sell more might not be possible to call; Microsoft probably has the best advertising, but if any of the 3 came up with "the next big thing" (for lack of a better term) they could take the lead regardless of the size of their ad budget.

I think another interesting question would be which companies would be robust enough internally to maintain a platform with just new IP, based not only on making games that appeal to people, but also crank them out often enough to maintain a deep lineup of games so people don't go for long droughts without new games. From this angle, Sony and Microsoft should both be fine. Both of them make quality games that plenty of people enjoy; Sony has the edge in terms of the number of studios they own, while Microsoft has had the edge in terms of actual sales (and they have been beefing up their 1st party side lately, recruiting talent for Black Tusk and creating Osaka, just to give a couple examples).

Nintendo, on the other hand, might be in a bit of trouble. They are well known for working hard on their games and coming out with quality products, but they rarely create new IP and they often see delays on their games. They could strike it big with another Wii Sports-type casual hit, or a more traditional Mario-type hit, but if they strike out with a new IP that can't leave niche status (see Pikmin) they could be in a world of hurt if they can't crank out another game quickly enough.

Valve would be my choice but console only I'd go with Nintendo.

What about third parties, do they exist in this scenario or are MS/Sony/Nintendo supporting there consoles on there own?

everything would be the same, but exlcusives / first party games (so no games like gears, either) would all be new IP's. no mario, zelda, uncharted, gears, resistance. third party games arent effected in this scenario

Nintendo.

Most of the time they incorporate their new ideas into their established characters/series, so all that would change is they would make new characters. And since their major studios wouldn't be focusing on continuing games to their established series, they would have many new IPs being rolled out. Sony and MS would definitely put some good competition but i think Nintendo would slightly edge them out.

Oh and as for who would sell the most, it would be Sony. Nintendo "fans" have a tendency of complaining for new IPs and never buying them when they're actually out. I don't know enough about Microsoft to comment.

it is hard to say because not all three have been put in a situation they need to create new IPs.

If Nintendo's IPs declined we would only then see what new shit they can come up with.

nintendo wouldnt last a month