I'm skeptical that JavaScript and WASM are anywhere near being suitable for any and all backend services.
For example, Cloudflare workers can't even talk to the outside world with anything other than fetch(). There's websockets, but only as a pair to talk to a browser that connected to you.
I'm a fan of Workers, but they do have limitations.
Likewise, there was a time when microcomputers weren't suitable for many applications. Sometimes a new approach (edit: and ultimately a better one) has to start at the low end and work its way up.
For example, Cloudflare workers can't even talk to the outside world with anything other than fetch(). There's websockets, but only as a pair to talk to a browser that connected to you.
I'm a fan of Workers, but they do have limitations.