>>39045770digimon has never been based around "catching them all." they never set that expectation in the first place, and everyone understands that (unlike pokemon) they've been working with limited budgets and resources.
that being said, they've actually set a goal to have all the digimon in a single game and they're working towards it. meanwhile, masuda is too lazy to keep including all the pokemon even though they had always been able to do it up until now.