Ever since USUM came out
My feelings towards pokemon have been on a decline since bw2, because not only did it kill the 3rd game trend that would've naturally grown into the single game, full experience or even single game sequels that expand on so much while giving a ton of post game as well, it overall just kinda killed all hopes for that happening
I bought into SM and surprisingly, enjoyed it despite ALOT of glaring flaws, but when USUM came out, all i thought was "yeah, BW2 DID happen huh..." And i ended up abhorring it overall more than BW2 as, at least those games, despite all their flaws and hopes crushing, tried
Everything else just kept going south and honestly it has made me regret more and more.
I wish we could go back to gen 3 or 4 honestly, those games had the least flaws and were nearing something wonderful...