people still like old nintendo games
nes and snes game ports have been everywhere since 2006
nintendo 64 has a smaller library than people like to admit, a few pricey titles though.
gamecube games have visuals that look good enough to be a recent nintendo release and a lot of them are obviously not getting ported. that and the small number of consoles sold compared to the competition drives up the supply/demand
wii will never soar up like gamecube games did but now is a good time to but shit like mario party, galaxy, zelda, donkey kong, super paper mario, strikers charged, etc for the wii. you can get these games for real cheap, even on ebay sometimes. and theyre the most likely scraps left at flea market and yard sale tables, surrounded by shovelware and xbox 360 sports games, obviously. wii games wont have a big day like gamecube, but they will have their day. consoles are pretty cheap too, be on the lookout there. also get ready for mario kart wii to turn into a booming competitive game a la melee. but theres so many copies of it in the wild im not sure how valuable it will ever get.
wiiu is a coinflip since a ton of shit got ported to switch immediately lol