@travisfw for some, it already is...
I know you probably mean a 3D interactive world, which is also probably possible, but there's a lot of people that just stay online here almost 24/7.
I'm sometimes one of those people. I love it here and would definitely check out a federated 3D interactable world if it had features that connected to Fedi proper.
Not sure about everything that could be possible, but personally, I'd *at least* want to use my own username and domain combination like Fedi proper.