< here is nothing inherent to any of the languages I mentioned that makes them slow.

I don't agree. The inability to explicitly allocate on the stack in Java and OCaml? The lack of threads in OCaml? Java GC pauses (by the time you're storing things off-heap you might as well be writing C++)? I don't know as much about Lisp, but when looking at a task X, I tend to give the benefit of the doubt to languages (or frameworks, or hardware, or people, for that matter) that have actually achieved a measure of success at X.