WebAssembly somehow does not seem to be able to break-through, unlike HTML, CSS, JavaScript did.

Or the people who write wasm don't talk too much about it. My OSS work (https://github.com/mickael-kerjean/filestash) has tons of it:

1. to create web versions of applications that are traditionally desktop only to render things like Parquet, PSD, TIFF, SQLite, EPS, ZIP, TGZ, and many more, where C libraries are often the reference implementations. There are almost a hundred supported file formats, most of which are supported through WASM

2. to create plugins that extend the backend and add your own endpoint or middleware as a way to enforce the code run in a constrained environment without the ability to send people's file out

3. in the workflow engine to enable people to run their own sandboxed scripts without giving those a blank check to go crazy

It is more of a silent thing. Running in the background, internal libs, deployment tools, plugin tools.

But also - it's lacking things like a unified positioning + required knowledge to understand it is quite large compared to average dev + most people have no real use for it. It's mostly too "abstract high level" and "low level" for most devs.