It does sound pretty cool! I wonder if a better approach is to have a single platform that will have more maps that are interconnected.
So far, I think that Zwift is taking this approach by expanding their maps and soon having an ability to choose which map (World) to ride in.
The issue with multiple platforms is that in each there are different settings, interactions and rules. Coming up with a unified standard between rules for creating maps, using a single rendering engine (that generate consistent visual world look) and physics (drafting, acceleration etc) is a huge barrier.
I really wish that one standard would emerge to make this a reality, but for the short future I don’t see it happening. So my hope is that Zwift will hire more talented map designers that would create spectacular and fun maps to ride in.