For me, part of the problem is that we have more than enough Pokémon. This is something I've said for years, and I stand by it. You can introduce new Pokémon here or there to drum up excitement – the way you debut new Pokémon like Lucario, Zoroark, etc. to get people interested in the films, Meltan/Melmetal to get people interested in Go/Let's Go, but there isn't a need to keep debuting entire new generations of Pokémon ...except that's what some people seem to want.
And it's these people that I feel are missing the forest for the trees when they get upset at the initial reveal of Iono as the new Gym Leader, apparently because it didn't debut a new Pokémon alongside. Who cares for the new Pokémon anymore? We have, like, 800 of them. A new game can feature new regions, new characters – new contexts for Pokémon to appear in, new methods of engaging with them, and sure you can have a handful of new Pokémon every now and again, but the value in debuting c.100 new Pokémon every 2-3 years is now well into diminishing returns territory.
I'm actually quite fond of a number of Generation 7 Pokémon, but I'd have to admit none of them explore new territory – they're all more or less redundant to concepts already explored better on other Pokémon. Nothing about any of the Gen 9 Pokémon we've seen really strikes me as "oh wow that's new", more "ok but they already did this on other Pokémon before and I'm quite fond of those ones."