Wasm as a compilation target is certainly of interest for the future. This Javascript target will hopefully provide a pragmatic way to write Gleam for a similar set of environments in the meantime, in addition to providing whatever unique opportunities the JS target itself offers.
If you like elm-similar languages, check out mint at mint-lang. It's very heavily inspired by Elm the language, but not Elm the community or project. I've been using it on side projects and love it. It doesn't compile to wasm, but it does compile to preact with web workers.
We would like to do that one day! It would take a long time though, so more impactful things will come first, such as improved tooling and documentation.