>>40158912My guess: Yokia Watch is VERY juvenile (like there is one about farting). So as kids get older, they don't continue with the series and age out. Pokemon is targeted at kids, but not in the way that would turn adults off. The combat is engaging and it's more themes that would appeal to kids (friendship). I remember I was in college around Gen 4 and a lot of college kids were getting back into Pokemon. It also helps that Pokemon are cute which appeals to girls of all ages where Yokai are kind of ugly. In short, it was never going to be more than a fad with kids.