Why would that matter? Adding extra CPU cores to the GPU sounds like a much dumber idea to me. You'd be wasting silicon on something that is meant to be used infrequently.

Is it really that difficult to imagine 1% of your workload doing some sort of management code, except since it is running on your GPU, you can now freely intersperse those 1% every 50 microseconds without too much overhead?

Cars are slow and inefficient in reverse gear but a car that couldn't drive in reverse would be broken.

You put “can’t” in quotes, so I guess you are quoting somebody, but I don’t see where the quote is from, so I’m not sure what they actually meant.

But I suspect they are using “can’t” informally. Like: You can’t run a drag race in reverse. Ok, you technically could, but it would be a silly thing to do.