I think you hit the nail on the head with this paragraph. If I'm a casual fan and I just want to watch soccer, and I don't care much about the teams involved, I'm going to pick Premier League, etc every time over MLS. They've got to get people invested in their local team.
So in light of the fact that the networks and ESPN are not clamoring for a bunch of Nashville-versus-Salt Lake City MLS inventory, I think the Apple deal is fine. $100 one time to watch every game of my beloved Houston Dynamo, plus whatever else games I care to watch for the entire season ain't bad in this day and age. No blackouts, no bullshit. Clear, simple. I don't have to go hunting for tonight's game or have multiple services. The NFL is starting to walk down this road and it's going to bite them in the ass eventually. I have to have the networks, ESPN, NFL Network, and now Amazon and Netflix to watch NFL every week? Nah, fuck that, I'll just do something better with my time.
They need to communicate better that you don't need to subscribe to Apple, I'll give y'all that. But this is just an MLS-specific streaming service that you happen to click Apple's app to access. MLB's TV situation is a total disaster in comparison. I'm not an NBA fan but I doubt it's better.