Most "real" modeling work on Roblox is done in Blender, exported to fbx, and imported to Roblox Studio. Complex models are typically not built in Studio.

Are you talking about a platform/portal where the published 3D web content (games, simulations, virtual events) can be discovered and accessed by users?

I was more referring to having a second product, that leverages the first one. So for example, if you have a simple 3D editor that doesn't compete in features with high-end 3D editors. What you could do, is have a game, where amateur 3d users can use that tool to build content for their own world. That is why I mentioned Roblox as an example.

The solution might be to develop a niche modeling solution with appropriately high level tools for your domain, as opposed to a general polygon modeler.