You're saying it like it's an absolutely good thing. Some (many?) users would rather pay the cost upfront in compilation time (doesn't really matter if it's AOT

You're saying it like it's an absolutely good thing. Some (many?) users would rather pay the cost upfront in compilation time (doesn't really matter if it's AOT or JIT) than pay the same cost many times over through a significantly slower runtime. JVM also scales up to supercomputers (and everything in between) if you want it to, so depending on your requirements a single-threaded alternative might not even be an option.