Well there’s actually a few very simple solutions/rebuttals to what you said.

1: They absolutely could fit a dynamax mode for every Pokémon in the game – if they can fit every Pokémon, NPC, and a region into under 4GB for a 3DS game, they can absolutely fit an extra model per Pokémon for a 12+GB switch cartridge. They don’t need 3-4 models per max pokemon. Just make the clouds separate models, not “model and 3 clouds, model and 2 clouds, model and 1 cloud” then repeat for every Pokémon, but “every model, 3 clouds, 2 clouds, 1 cloud”. Takes about 2400 models out. Or, yknow, have an indicator on the battle menu instead of a cloud model to convey the time you have left.

2: The point isn’t that you can’t bring in your “old teams”, it’s that if your favorite Pokémon isn’t available in the wild of Galar, you can’t get it period. You couldn’t catch a Treecko in Alola, but if you wanted one, you could trade for one or bring it up from a previous game. But now if it’s not in Galar, you just can’t anymore. If your favorite Pokémon isn’t lucky enough (or from Gen 1-2 because let’s face it, they aren’t going to cut those guys because nostalgia is a powerful sales tool), then your favorite Pokémon isn’t allowed anymore.

We criticize Bethesda for half assing things, we criticize EA for intentionally chopping up games to sell you more shit down the line. If GameFreak is gonna do both, it doesn’t matter how long I’ve been a Nintendo fan, I’m going to call it out.

They clearly could have included them but decided not to. It obviously wasn't a coding or memory issue.

If it were another company, we might see the missing 'mon as DLC. That's not the case here, so they aren't doing it to extort more money.

This means you either assume they're doing it to be evil, or that they felt the experience was improved with a smaller dex. I think the number of people assuming the former is frightening.