Doesn't LLVM (or a related project) support JIT compilation?

That's right, LLVM does support JIT compilation. But it's just one tool in the toolbox. I would hazard a guess that most projects which depend on LLVM don't use the JIT compiler.

But even with a JIT compiler, LLVM doesn't provide the kind of runtime services (e.g., memory and resource management) that we would typically associate with a VM runtime like the JVM's. Like their Web site says, "Despite its name, LLVM has little to do with traditional virtual machines, though it does provide helpful libraries that can be used to build them."

Note the lack of technical claims that one is superior to the other, thanks for pigeonholing what I was getting at.

I don't think you've communicated what you were trying to accomplish very well with your LLVM comparison. Many people will see it and think you're confused at what you're talking about.