forever is a very long time... I'd stick to this generation, and yes I think neither has much chance of catching Nintendo. Overall Sony probably still has better chance than MS but its looking very slim for them too.
MS has for me succeded (particularly in US and UK) in taking PC gamers to console - FPS/shooters/strong online MP. While they are great copiers of others strategy I agree with Nintendo comments and think MS would really struggle to compete for casual, fun games. Also they have very bad market perception to go after that market now. I know familes getting Wiis and to them 360 and MS = violent games for teenagers. They'd never even think to look at the console and unlike us they don't check internet to track gaming trends.
Sony does of course have IP/history with fun family fare but has so far got itself lumped more with MS this gen than where it used to be. But the brand is still there, they can still get out stuff like LBP and are in a far better position with IP like Jak, Sly Cooper, etc. to do so.
I think they have too big a ship to turn around now but their brand and IP does give them a chance. MS, I feel, have near enough no chance to get that market and would likely only harm their perception in the market where they are strong - hard to imagine all those 18 to 26 year old Halo, GTA, GoW fans liking the fact their console is now for the kids!
Try to be reasonable... its easier than you think...
