This argument is going nowhere if statements are made purely on authority.... Regardless which side, if any, you're on, the fact is that AH player growth had stopped when the arenas got to a certain uncapped size. Once they were capped subscriptions resumed increasing. It's from this and other facts, and from working to establish other facts rather than unsubstantiated assertions, that this arguments must work from if it's to not turn into another food fight.
E.G. that the game must be persistent, and that this isn't how things are now.
What is supposed to happen once a map is won, that would not "break" persistence?
What are the facts of gameplay quality when AH was at its peak in single arena population?
etc