Problem is I don’t think there is a reasonable solution that wouldn’t affect everything else. I wish there was, but it’s way too complicated. Your idea of splitting GAC into an active and inactive branch means two smaller GACs. Smaller GAC means smaller leagues, which in turn means smaller divisions. Even if you only pulled the inactives out of Carbonite, Kyber divisions would shrink. The GAC doesn’t maintain it’s current state with a change like this, it would have to adjust downward. And that doesn’t even cover potentially adding an incentive for people to go inactive.
No system is perfect, sometimes it’s better to live with the flaws.