Microsoft Confirms Plans To Release Xbox First Party Games “Across All Platforms”, Including PlayStation

I don’t expect Microsoft to commit to this plan for the foreseeable future.

It's not a plan, it's a lie to calm down regulators. They tell that lie since before the Bethesda acquisition where at Bethesda claimed "of course MS will bring our games to PlayStation, anything else would make no sense" and MS said "yes, we will bring our games to PlayStation but decide on a case by case basis". Other than remasters of games from three decades ago, nothing happened. There isn't even a PS5 port of Minecraft even though the PS4 port was outsourced to a 3rd party, so subsequent claims of MS not having PS5 dev kits for a port is obviously another lie.

It would be an odd move if Sony didn't plan to do the same. They'd give all the exclusive power to Sony and effectively kill any reason to buy an Xbox in the first place.