It's not your imagination, the 1.0 version of the spec was/is widely referred to as MVP - "Minimum Viable Product" - and it was an ordeal just getting that across the finish line. It's why so many things are missing. The rest of the ecosystem naturally inherited that state of readiness.
EDIT: I have to disagree though - emscripten is actively maintained. Not sure why you get the impression otherwise.
We're using emscripten in production right now. New stuff is committed to its github repository every week and there are new releases. I think you're confusing "wasm32-unknown-emscripten" for "emscripten", the latter is a product you can use to compile software.
EDIT: I have to disagree though - emscripten is actively maintained. Not sure why you get the impression otherwise.