That's like saying Disney didn't mature with its primary audience. Pokemon isn't made for people in their late 20s, early 30s; it's made for and marketed to children.

I say this as a pretty massive fan of the franchise; I only skipped gens 4/5 because I didn't have the personal disposable income to buy a DS. I'm sure VGC[0] is the primary reason most adults choose to purchase the new games, among those who do.

0: https://www.pokemon.com/us/play-pokemon/pokemon-events/pokem...