MLS is not going to go to 40 teams. 32 MAX I agree. I also think 40 teams is never ever in any universe going to happen. Even if it did you can't just put a team in markets simply based on population. It just doesnt' work that way. Population isn't the only metric used to determine if it would be a good soccer/MLS market. You seem to be under the misunderstanding that I was saying that I actually thought Harrisburg and Colorado Springs would get an MLS team. I do not.
You won't see a regional setup in MLS because that would have a detrimental effect on TV revenue. But Div II or Div III will be gate revenue driven more than TV contract driven, so regionalization is in their best interests to keep costs down.