There have been CPUs which could execute Java bytecode directly…
And not just actual Java processors, ARM has/had an extension for that: https://en.wikipedia.org/wiki/Jazelle
I remember there was Linux Journal article about it, almost 20 years ago, regarding Java.
Also this is how mainframes like IBM i work. Binaries use the TIMI format and are JITed into native code at installation time or on demand, if needed.
On the other RM Stallman also resisted everything Java, because it did not mesh with his vision of the future. (Prop up everything GPL, unless the proprietary solution is already an industry standard.) My favourite example was how GCC was on the cusp of getting a backend which could emit Java byte code. Imagine that!
That could have kickstarted all the JVM languages a decade earlier. Alas, many forces were against such things.
Now, we have everything on everything, but most of all Javascript everywhere. Weird. :-)
http://mail-index.netbsd.org/source-changes/2013/10/16/msg04...
In any case, you could extend this beyond just user mode. Currently the domain of safe ring0 execution is eBPF as far as I know, but this would be way more approachable and other operating systems could implement it.
I've got no idea what the future is for this project but I really hope it doesn't stay in the realm of "fascinating but not practical."