Imagine that there was a game with a growing amount of customers, producing even more profit every 2 years, that suddenly decided to stop making content and lose all of its customers, declaring the next expansion the last. If you really believe they would stop when the active population is now in the millions, then the logic you are using is incomplete.

If level bloat is a problem, I expect they will either stop bothering with levels and focus on horizontal progression or do a level squish (probably reduce ARR to level 30).