> An AI that can only perform at the average human level is useless unless it can be trained for the job like humans can.

Yes, if you want skilled labour. But that's not at all what ARC-AGI attempts to test for: it's testing for general intelligence as possessed by anyone without a mental incapacity.

It seems they don't test for that, since they use the second-best human solution as a baseline.

And that's the right way to go. When computers were about to become superhuman at chess, few people cared that it could beat random people for many years prior to that. They cared when Kasparov was dethroned.

Remember, the point here is marketing as well as science. And the results speak for themselves. After all, you remember Deep Blue, and not the many runners-up that tried. The only reason you remember is because it beat Kasparov.