I believe 8-bit games aren't outdated more than they are a "style" than often used nowadays, but it's kinda like music. Just because, say, ragtime or baroque is not culturally relevant doesn't mean people who like that music can't compose NEW songs in that style, or even do GREAT new things with it. When a style is established, it's there forever. Whether or not people want to return to it, it's up to them. History's shown us people, despite looking for new ideas, have a facination with that which came "before".
Interestingly enough, I think the 8-bit movement, now, is more liberated, because they aren't tied to what they can and can't do as far as Nintendo of America dictates. Look at Oniken and the decapitation sprite animation. That could never be done back in the day. Now, there are so many awesome possitibilies regarding 8-bit gaming, it's pure awesomeness in itself.
Hell, I think big companies should jump on that wagon. Kinda like Capcom with Mega Man 9 and 10, get some teams to do NEW 8-bit games. Obviously those games won't have a big bloated budget, and you could release them on PSN, XBL, Wii U, IOS/Android/Ouya, Windows/Linux and go crazy. Hell, big NEWER companies could even reimagine new properties in 8-bit(Rastan-esque God of War, Price of Persia-esque Assassin's Creed). It's an interesting venture.