Are the mainline games becoming less important? Missing a load of pokemon is a dangerous move as the real big money is in merch and cards. Especially when it is a big merch mover like slowpoke. You want that promotion.

But they appear to be in the anime, they are in Go, they could end up in Masters if it doesn't die first and they certainly have more spin off apps in production. The mainline games might be less of a focus for TPC now, they aren't as relevant for promoting the pokemon.