It's still gonna be really expensive for ESPN (and/or MLB) to clear up those 24 other teams' local streaming rights (and for the big-market teams, Phillies included, and their existing RSNs to be made hole.
MLB really got played here, they lost $1.65 million from ESPN's original deal, and then merely got that same amount back by selling them MLB.TV and making this three-year deal. The extra they are getting from all the other companies still doesn't close the gap, and they no longer get the annual revenue from owning MLB.TV.
What's not clear to me is did ESPN buy the six teams' local rights or is that just part of this three-year term? But whatever happens in 2029 there will still be streaming, and ideally no more blackouts or local limits.