In the 1990s I was building, among other things, web-based controls (in Java) for backend systems. People were completely blown away with what could be done. (The major competing technology was HTML forms and HTTP PUT with Perl CGI.) With the exact same language I was also able to build a high-performance peer-to-peer file sharing system for backend systems. (2+GB files to personal workstations across a large geographic area through ATM -- practically in real time compared to the NFS alternatives.) There was every reason to believe that Java's portability and just-in-time technologies would dominate the computing landscape. I think we can look to Sun Microsystems (and now Oracle) for reasons why Java was eclipsed[0] by other technologies. I have no idea what kind of longevity WASM will have, but I have seen so many technologies come and go over the decades, I know technical excellence is not the primary predictor of what stays or goes.

[0] Yes, there is a pun buried in there.