The kind of people who will read a media blog are, on the whole, the kind of people who consume a lot of stories to begin with. And once you take in enough of them (probably by the time you’re in middle school, really), you start to see certain patterns keep showing up.
Where monster-catching series (and their merchandise) were laser-aimed at kids, they predictably had some soft core Aesop around “teamwork” or “friendship”. But I don’t believe that a single one of them executed on it half as well as Digimon.
I’m a long-time fan of the Pokémon franchise, including one of the longest-running animated series still being produced. Now, the Pokémon anime looks to be lining up the TV-season equivalent of a Greatest Hits album.