It appears that there was another reason why Sony have decided not to join in the Minecraft cross-play fun. Mojang CEO Jonas Märtensson gave an interview to PressFire, which has helpfully been translated by NeoGAF, and it reveals a previously unknown requirement.
When asked about how the cross-play would work on Nintendo Switch Jonas mentions that you will need an Xbox Live account.
“That’s pretty unique as well! But everyone that’s in on this, all the platform holders, have been pretty pragmatic and understanding of that what we’re trying to do is create a good experience for the players. We needed a good system to connect everyone, and Xbox Live is a good system.”
Of course there is no way in hell that Sony are ever going to say you need an Xbox Live login to play a game, so it’s understandable why they have backed down. Nintendo are still taking baby steps in the world of online gaming, and adding players to their small install base is also a good idea, so you can see why they signed up, even if it does mean working with a competitor.
Of course that doesn’t explain why Sony are not allowing cross-play for Rocket League, Microsoft have no involvement in that game.