>>18221889because the anime came first for most ~90's kids~, so even the ~hardcore~ pokemon fanbase has it deeply rooted in their hearts
there's gonna be someone who gets mad at that statement but it's true. most of the older fans who currently follow it got into it when they were younger so they just keep following it
>>18221973and this too. tv shows get wider audiences by default
not to mention until viz restarted the localization the audience for the manga was limited to just those willing to seek it and read scans online. that narrows it quite a bit
