Java bytecode was originally never intended to be used with anything other than Java - unlike WASM it's very much designed to describe programs using virtual dispatch and automatic memory management. Sun eventually added stuff like invokedynamic to make it easier to implement dynamic languages (at the time, stuff like Ruby and Python), but it was always a bit of round peg in square hole.

By comparison, WASM is really more like traditional assembly, only running inside a sandbox.

Just like CLR bytecode, IBM i TIMI bytecode and many others since 1958.

For some reason when people advocate for WASM outside of the browser, they only remember of the JVM.