It sounds like Sony/SDS simply got played. MLB is never going to take it off of Gamepass and most Gamepass subscribers aren't going to put up with over-the-top, EA-style MTX unless the gameplay vastly improves, and even then there's too many great games on Gamepass to dedicate hundreds of hours into one.
Ultimately, I'd be surprised if SDS is still developing the game in 3-4 years. They're now developing a game that went from a "system seller" to one that is theoretically hurting playstation sales.