Remember back when playing games with friends was messaging them on <whatever> and saying - "hey - i'm playing quake on the <whatever> server, come join me if you want!"
I remember even playing Quake 3 cross-play on my friends dreamcast with controller, against PC people. It was literally like bicycling over to a car race to try to take part and getting run over by a lambroghini. I thought 'what a bag of poorly thought out dogshit.'
But then again, the concept of crossplay was so simple back then. Social gaming wasn't a thing. Parties were barely a thing, voice chat didn't exist really. I think dreamcast quake just bombed you into the nearest PC server. Basically any kind of game that had a fleshed out multiplayer either had nothing, or it had game specific account bullshit.
So I continued to play on PC, which had me logging on to all sorts of multiplayer account systems to get anything going, and was a complicated mess. It's been streamlined somewhat, but you still need a steam account, a uplay account, an EA account, a battle.net account, a discord account, a skype account, a teamspeak account, and westwood chat (ok i'm trolling now).
When the Xbox game along with Live, it was a breath of fresh air, a paired down, simple intuitive way to play with friends, party chat, headset in the box (completely separate audio output from game sounds - cool!) which since then has been pretty much ripped by Sony (for good reason), and has become a ubiquitous part of gaming. Friend requests, invites, parties, joining games together, playing together - no bullshit, no pecking out messages and coordinating with third parties.
No wonder most of the western world plays on these setups. Complexity is a curse.
Now if Sony/Microsoft/Steam got together and hashed it out, I'm all for it, it would be a lot of work, but I wouldn't say it's impossible. Sony has done it with certain titles and Steam, etc, in the past. Microsoft have always been obstructionist traditionally. This is a new world of potential since they overturned their stubbornness a few months back (after Don Mattick wrecked their brand).
So things are changing, MS are keener, Sony are as keen as they've always been, more keen than MS of the past, but apparently less keen than a MS with a dwindling market share.
But if you dig into what is ACTUALLY on the table here. It's rocket league, minecraft, and a maybe 1 or 2 other potential titles.
First of all, Rocket league does not have crossplatform play, and not because of Sony, they pretty much don't have it at all. It has a crossplatform matchmaking pool only. Go ahead and try it out. Good luck inviting your Steam friend to your Xbox Party. All you can muster is a dopey little private head-to-head game, if you name and password protect a private game lobby and coordinate a third party communication. 99% of what people expect from the crossplatform rocketleague dream is not this.
Minecraft crossplatform is basically 'please create and sign in with an xbox live account on that PS4 to play minecraft with other people'. Sure, maybe Sony should allow this, but is it so crazy to understand if they are hesitating to do it? It might end up making whoever is in charge the worst Sony CEO of all time long term. You think if Sony bought Call of Duty during it's (and the xbox 360's) prime, then announce crossplatform, (all you have to do is sign up with a playstation account on your Xbox) - you really think MS would have allowed that?
Whatever way this swings, to me, unless some omnipotent programming being comes down and dictates to everyone, this isn't going to happen at any speed. If anything happens it's going to have lots of bullshit third party publisher accounts per game, and it's not going to be as good as partying up and playing with people on your native ecosystem.
For the media, and everyone else to spin this as a simple 'sony are douchebags, they just have to let psyonix flick that switch!' is just not helping progress this, it's confusing everything.