You didn't make a point. Training generative models on their own output after filtering for quality is a well known technique for improving image quality for a single mode. This can happen automatically when generated images become popular on the internet.
"Excellent, let's see how your car goes faster when you push the gas pedal"
If you are saying that hypothetical client knows a better song/artwork/code from worse, boy are you in for disappointment...
My point was that insane amounts of curated fully original works were required to get the output of these generative tools to the "occasionally impressive" level it is at now, and those original works exist precisely thanks to copyright. To say "oh we don't need copyright now" is to saw off the branch on which this hinges.
If you are into this stuff and want to see it become better you should rather promote copyright and differentiation of fully original works.
(By the way, do you have an objection to my point? I must have missed it.)