I'm not that in the know with pre-third generation kpop but there seems a fairly consistent theme with out with the old and in with the new amongst kpop companies abandoning their old groups when new groups debut.
I've already mentioned in the tags 2NE1/BP and CLC/G-Idle but are there other groups that were thrown away for the fresh new group and conversely arr there groups to survive the introduction of their newer/younger Dongsang.
One might even make an argument that with the slow and steady rise of Stray Kids led to the downfall of Got7....