I mean, originally the whole point of MLB.TV was, "finally, you can see all the games from your team that aren't on normal/national TV!" It wasn't meant to include the latter and nobody cared if it did. And the only thing irksome about it was when Fox would do a regional broadcast but had the exclusive window, so, for instance, if a Dodgers game was on in my town I still couldn't watch the Phillies or any other game.
Now that everyone is cord-cutting and so few games are even on over-the-air Fox, things are a little different. But if anything the blackout rules are even more valuable to ESPN and Fox than they were before. For those billions of dollars, they still want/need people to pay those cable carriage fees or subscribe to a streaming provider or buy ESPN+.