>>39538783It's not about the pokemon having dex entries with flavor text, location data, height, weight, cry, ect. It's about the pokemon being coded into the game at all. Gen 7 didn't have the national dex as an in-game feature but all the assets and data for each species was on the cart and you could transfer them all to the games and use them as you please. For the same reason gen 3 wasn't THIS bad, it was bad you couldn't bring your old gen 1 and 2 bros forward but it was at least a hardware incompatibility that Game Freak had nothing to do with and the pokemon were still in the game if you wanted to action replay them in or wait for the other games they were catchable in.
