The sandboxes are different. The embeddable Java plugin sandbox was a bit different and susceptible to confused deputy and other attacks. So yeah, I guess you can say it is iterative but they’re kind of worlds apart. You can run thousands of wasm modules in a single process and have them all be completely isolated. Its performance and security gains, portability, and usability are all superb.

I guess I can’t really defend it well, but I think it is interesting and important.