90s-2000s pop culture was a lot harder and teenage culture/early 20s culture was a lot more rooted in "being cool". So I think that was a factor too, though Nintendo didn't do themselves any favors with stuff like the GameCube being purple right when Barney The Dinosaur was associated with all things kiddie and meanwhile "kids" are all about Eminem and 50 Cent.
I do remember friends I grew up with who were all part of the NES generation and crazy for Nintendo then, wouldn't dare touch a GameCube or GBA by the early 2000s and I remember being really vexed by that. It was all about the PS2 or Halo.
I think that has eased, the music industry doesn't drive or define all pop culture and no one cares if you're wearing brand sneakers or a t-shirt or jeans anymore. I think this generation of teenagers and early 20 somethings have more latitude in enjoying things they want to enjoy. So if you enjoy Super Mario or Spider Man or Batman or Zelda as a kid and you still like those things at age 21 ... no one really bats an eyelash anymore.
But Nintendo also does a way better job today of marketing to 20 year olds and the Switch looks "cool" design wise, it doesn't look like a toy if you don't want it to.










