Some of us will no longer be watching sports by the time all of this really shakes out. For now, it sounds like nothing will change. The ESPN networks will be on cable (where they still have 65 million subscribers, down from 100 million), they'll be on YT (10 million) and they'll be on Hulu/Fubo (6.2 million).
And then if you want ESPN networks on their own you''ll be able to get the flagship thing for 25 or 30 bucks, or if you want Venu you'll be able to get that for 40-50 bucks.
It stands to reason that Disney may wish to buy or squeeze YouTube going forwards, since they only get a $10ish carriage fee there.
Phillies Comcast deal doesn't expire until 2041 so MLB is going to have to figure out how to accomodate them (and the Yankees) on any new streaming deal. For now of course it will just be Peacock. But I suspect we're not a very representative group both as hardcore baseball fans and technology adapters. The overwhelming majority of viewers for any given game still comes from cable and it's going to take a couple of decades for that ratio to flip (and many younger fans just don't care about watching entire games at all).