They more or less managed it in 8th. The game was in a good state, things were more or less balanced. But GW released new things and instead of these new things fitting in the meta, it shattered it. And then 9th came around and in the development of 9th, GW did something to co-opt the ITC and NOVA.
That I think is my biggest problem with 9th on a whole. We went from Eternal War, Maelstrom, ITC (and other variants), Open War cards and even narrative missions to just Eternal War and Crusade missions which mostly use the same scoring as the Eternal War missions. Before we had constant variety and now each mission is practically the same, particularly if you are playing competitively, because the best Secondaries are ones that don't depend on your opponent, so you take them every game.
Anyways, I do fully support getting the ITC to be releasing rules again. However tournament players apparently don't want that. What they want is the rules to stay the same no matter where they are playing, so they only have to master one ruleset.