It's pretty much market price, though if you only care about the Phillies or even just one other team, not as appealing.
In Los Angeles, Spectrum offers a streaming-only plan for Dodgers games for $29.99 a month, the same prices NESN charges to stream Boston Red Sox and Boston Bruins games. YES charges $24.99 a month for New York fans to stream Yankees and Nets games.
NBC Northern California is $17.95 (but that's for the Sharks, A's and Kings, not the Giants or Warriors).
NBC Boston is $14.99 but that's only for Celtics and Connecticut WNBA; you're paying almost $35 if you want that plus NESN.
Your comment about Peacock just makes me happy to keep paying for YT for now, the Multi-view, the DVR and on-demand and the overall simplicity of having ESPN, Fox, CBS and a few non-sports channels is still worth it. Plus I travel a lot so it's easy to use in hotels or other people's houses. I'd be blacked out for Phillies when travelling otherwise (though I have free MLB.TV).
I'm sure there will be a lower price point once there is integrated national black-out free MLB.TV for all 30 teams but that has to be negotiated by MLB with Comcast in the Phillies' case.