Gamefreak isn't favoring gen 1 they're favoring popular Pokemon, many of which happen to be in gen 1 but not all of them are. Tyranitar is gen 2 and it's getting shilled. Gardevoir is gen 3 and it gets shilled. Rotom is gen 4 and it gets shilled. How are you seriously gonna blame gamefreak that pokemania inevitably ended and Pokemon don't catch on as much as they used to? It's not like gamefreak even shills every gen 1 Pokemon, it's mostly just the most popular 5 or 6 of them. You don't see gigantamax Jinx do you?