Is there a hard cap for the growth of MLS based on the geographical assumption that the MLS will never put teams into the Champions League. To become a great league, and by that, I mean one that can compete talent wise with the big 5 Euro leagues, you have to have great talent. That means having great players play in your league in their prime, not when they are just looking to cash a few more checks before they are simply unable to play.
I just don't see any of these kind of players...
Hard Ceiling for MLS