Ever since Oracle accuired Java, it got bit annoying in some parts. Of course there are now milllion plus one open source Java JDK/JRE implementations, but it adds another level of complexity.
Previously it was Sun Java, and everyone used that, which was clear.
Now compability between JDK’s is like “sure, SHOULD work, but no quarantee”
Server-side works better, webassembly and fat client on general imo aren’t worth it. It’s benefits require millions of users.