Or GF could just place some regional Pokemon Breeder NPCs that gives one random egg to the player, much like the first baby eggs at Johto daycare. That easily solves part of the problem and encourages trades at the same time.Regional Variants: The less significant of these two special groups, but still worth bringing up. Regional forms are inseparably tied to their region of origin in a way that no other Pokemon is. Muk is the way it is in Alola specifically because of the conditions of that region, Linoone gained new traits just for Galar's environment, so on and so forth. With that said, how are they gonna re-introduce these Pokemon in future games and generations? Will they be locked in some kind of "transfer hell" for prolonged periods of time, or will they try to shoehorn them into future regions? These questions would apply even if Dexit never happened, but considering it is in fact a thing it's even more important for GF to determine how they're gonna handle older regional variants so they don't disappear for several generations on end. I posed this question on a Discord server and it was brought to my attention that in the Let's Go games, you can trade with tourist NPCs for the Alolan forms of the Pokemon you give them. I guess that's the easy way out of this little problem, but it could get tedious and boring if done for multiple generations in a row.
Still, we would still have problems with pokémon like pikachu, exeggcute, cubone (and maybe koffing?)