As I said sprinkle a bit of benchmarks polluting the training and you have your loop. Each iteration will be better at benchmarks if that's the goal and that goal/context reinforces.

Sprinkling in benchmark training isn't a loop, it's just plain cheating. Regardless, not all of these benchmarks are public and, even with mass collusion across the board, it wouldn't make sense only open weight LLMS have been improving.