Comment by ChrisRackauckas

The part that made it much more feasible is that WASM's "new" GC ended up working nicely with Julia's GC, so WebAssemblyCompiler.jl was able to hook into it. With that, a lot more codes suddenly work because array allocations are fine. It means that in this state if someone took it seriously I think a pretty good version could be had in like 6 months, but it would take a real effort to make that something actually part of the "normal" maintained compiler stack.