For not fully featured 3D editors (which takes so much work, I won't even get started), I think the trick would be to bundle it with something that uses the output and that part generates the revenue. Roblox is a great example of that.
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.