For instance if EA was to create a shared universe you would be able to go from The Sims into Need For Speed by pulling up next to someone & asking if they want to race or you can walk onto a basketball court & start a pick up game to start NBA Streets.
The thing is, it's not that simple. We've had several experiments like this in the past:
PlayStation Home was once supposed to be a place where you could meet people and then play games. Unfortunately, it never got to that point, I think, because integrating all of them would have required massive work.
Would it be an MMO that you can add sections where you can play games? That service would not be cheap. That is what most companies are trying to build with the idea of a metaverse. And they're all failing because no one wants to accept someone else's standard over which they have no control. To use your example, EA should maintain an extra service, an extra game, in which you have a character and jump around to meet people and play games. The dream is this seamless experience of a GTA in which I go to the races and race. Or I go to the courtyard and play? It sounds fantastic.
Except, no one wants to do that. If you want to play a game, you're probably launching the game or opening Steam and inviting/joining your friends. That is as seamless as it gets. That service above would cost a fuckton and would not be seamless since you'd still have to install and load every single game. It'd be costly padding between the fun.
The Metaverse, as a mainstream idea, is failing. Only crypto bros are interested in it. I'm not pulling this out of my ass, I worked for a company that does that for almost 2 years, and I've seen millions being burned into something no one wants.
I can see something like that working only if Fortnite and Roblox decide to create "live" lobbies where you can meet people and play different games. But it won't be a seamless, big game; it would be more like a small room where you can talk to people and have different experiences.
The best you can have right now is open-world games with a big number of nicely crafted mini-games.
TL;DR
Companies have no incentive to build an MMO that would work as padding between their real games.
Players might think they want the padding, but they don't