those weren't "real" cores. you know what current chip has FUs that it falsely calls "cores"? that's right, Nvidia GPUs. I think that's the answer to your question (pushing 20k).
In what way were they not “real” cores? They had their own operating environment completely independent of other cores. GPU execution units on the other hand are SIMD--a single instruction stream.
How are GA144's nodes / "computers" not real cores? They're fully independent, each has its own memory (RAM and ROM), stacks, and registers, its own I/O ports and GPIO pins (some of them), and so on.