The short answer seems to be no. But in his response, he talked a lot about file formats and how they might differ for things like a pair of virtual shoes and wheels that fall off a virtual car. That might make any interchangeability would be a tricky problem to solve; companies like Roblox, Meta, and Epic Games would have to agree on file formats that could sync across systems. My sense is they might be reticent to do that right now.
I asked David Baszucki about the potential of interoperability between different virtual worlds platforms.