I agree for the most part but you're overestimating how many new Pokemon Gamefreak makes these days since Generations 6, 7 and 8 introduced less than 100 new Pokemon each iirc not counting regional variants and Megas which aren't actually new Pokemon.There are too many Pokemon.
With every new game, Game Freak introduces roughly 100-120 new Pokemon. There's currently, something like 890- that's not including the few new ones we're getting in the DLC. GF has painted themselves into a corner. With SW/SH they pruned the Pokedex despite some really heated fan-backlash. I believe that's an issue that will get worse, not better. If GF had a problem with the Pokedex because 800 mons were too many, what happens when the number hits 1,000 or 1,200? They release a NEW (not a remake) mainline title about every 3-4 years, so if they continue with this pattern we'll get another game in 2022/2023 with more new mons and probably less Pokedex/Box space. Despite the harsh criticism they've received over the lack of a National Dex this time around I highly doubt we'll ever see it in a mainline Pokemon Game again.