>>723497830
A majority of the demographic that fell for Pokemania eventually grew up by that point and either matured their tastes (if not turned outright-normalfag) or played "cooler" new fads like YuGiOh, that's why. Pokemon is primarily aimed at new generations of kids every release where it's still very popular anyways, the adult autists who never grew out of the series are just a bonus in TPC's eyes.

While I'm sure gameplay elements changing between Johto and Hoenn were a small fraction of the reason too, this is the same series that sets the absolute low-bar for AAA development yet still runs laps around CoD in sales. It's pretty clear quality has no significant impact on this franchise.