SEGA's IP's are not that valued to begin with hence why the subscription deals are attractive. Specially for old worn down content. If SEGA had a COD or Battlefield level IP inhouse then it wouldn't be as welcoming to "devalue" their IPs. Even with Persona, we are still talking old ass ports or for Yakuza, recouping dev costs on a non-selling platform and hedging on a potential dud on the selling platform (absolutely a no-brainer for a mid-at-best IP). It's not so much devauling something that has very little value to begin with compared to the rest out there.
If you look at the many pubs there are, Sony's money is better placed going elsewhere, and naturally that has been the decision made - with Capcom IPs for example. Square is Sony's favorite Japanese bum that Sony likes to prop, with Konami on occasion as well. That leaves SEGA out with their geriatric mismanaged IPs, and mid IPs. Naturally SEGA will feel like they're being left to the way side, and of course that's what happening so they'll welcome a desperate MS, and MS welcomes a desperate SEGA in a tight embrace of old mid at best content on one side, and survival revenue stream on the other. I see nothing wrong in that equation. Only thing I harp about is that if you're going to do an exclusivity deal or marketing deal, your clause better be 100% tight shut. MS doing that is competence. Sony not doing that is stupidity (unless you're getting the deal for peanuts aka a massive discount).