Games don't need to be graphically ground breaking to be fun but the art should at least not be repulsive and/or incoherent as fuck like modern Pokemon games.

“devs too focused on making a game pretty instead of fun” is talking about making the art photorealistic with fancy hair engines and such, when doing so doesn't add meaningfully to the experience and only serves to needlessly complicate development and inflate the cost.

We can tell that making all these 3D models and animations is a problem for the devs because they've said so repeatedly. They've even said they can't have every Pokemon in the same game as a result. Instead of the lovely pixel art of FRLG we have a mish-mash of dead-eyed, poorly-animated cartoons with PSP-quality "realistic" terrain that grate against each other. And for what? Why do 3D when you can only do 3D so poorly?

When people say that I think they mean they want games to look like this:

Or like this.

So, still atmospheric and beautiful, but low poly enough that artists don't have to spend so much time creating detail. Sort of like an impressionistic painting.

To be honest though for most AAA games I think its animations and highly choreographed gameplay sequences that are bottlenecking development more than the art is. Look at games like cyberpunk and fallout 76: they largely didn't have unfinished art assets (in fact the art assets in both those games, particularly the environments, look quite good). Instead they had broken animations and gameplay systems. I guess art style does play a roll in that though, as a more realistic model kinda demands more realistic animations to avoid looking weird.

That would be more valid here if Pokémon were focused on being fun. As a lifelong fan, modern Pokémon games are typically both ugly and not terribly fun. They make decent "turn off your brain" games, but the quality of game did not go up with the decrease in graphics.

New pokemon games are neither so that doesn't really work