Does anyone know how RE4 has sold? Hope word of mouth did it well. I guess it's sort of tarnished in this argument because Nintendo didn't make it and it's not exclusive, but it seems like that "big" game for adults that you buy a system for. Too late I guess.
Those other games really aren't good examples, their middle of the road at best. GAF aside, no adult is going to buy a GC based on trash like 1080 or PN03. I bought one for ED, but I already had the other two consoles.
I think basically adults buy, and will continue to buy at least some, Nintendo consoles because of the main IP's. Mario platforming and Zelda. I don't think people really care about Metroid, it could dissapear next gen and the casual gamer wouldn't miss it that much. I'm not that casual and they do nothing for me beyond their polished exterior.
Nintendo is stuck. They make money off of being kid friendly and re-exploring their established IP's. At least they have those, they never really have to take a real gamble and they can stay away from 3rd parties IP and commercial licenses as much as they like. At the same time, it makes them seem a bit stale when they don't develop to the next level, like they so obviously haven't this gen. Basically, you see even their best IP's like Mario and Zelda being forced into a template of the series. That's fine because their some of the best games ever made...it's not that great because the magic that set the foundation for all this is not as fresh as it was.
If they can stay above water and find some designers to replace the old guard (Miyamoto, good luck!) they'll probably recapture some of that uniqueness some day.