>>531585404
They are shackled by the gacha elements in this regard. If they make an outlier ID like Mao Faust then all IDs that come after are compared to her and if they're worse, deemed not worth having so they make less money. But if they continue to make stronger and stronger IDs on that level then old ones become completely irrelevant and content becomes even harder to balance making the playerbase upset.
This season's IDs have suffered from trying to tiptoe that line which has made them mostly end up as good but not mindblowing so people find them boring.