It looks like Barstool was causing Penn some regulatory hassles. For example, one of my favorite personalities is Barstool Big Cat. He comes on the local ESPN radio station regularly and is highly entertaining. Apparently, he is one of the main Barstool sports betting experts and his tongue-in-cheek named "Can't Lose Parlay" got them investigated by regulators in Massachusetts. But, I think PENN was mostly happy to be rid of Portnoy and all his controversy.
Interestingly, it is PENN that is paying ESPN in this new partnership.