That's a fine baseline
if your plan is to otherwise eliminate cars.
Otherwise "it's better than humans" is in fact a win.
When I had Hodgkins, I found out there is no baseline data for untreated patients. Scientific medicine was invented after the first cures for Hodgkins, so by the time anybody knew "We should measure properly what happens if you do nothing so we know whether we're improving on that outcome" it would be unethical because you're giving people a death sentence in order to do science, which, you know, we outlawed that because of the Nazis.
We can assume not treating Hodgkins is extremely bad but we don't have scientific data, because all the untreated people in a civilised country self-selected - they said "No" having been told that means they'll almost certainly die, and right soon if they say "No". That's not a normal sample, that's... crazy people maybe? Very religious people? Not normal. But we don't have actual baseline numbers.
However, although we don't have a baseline, we do run trials, they compare against what we're currently doing, called the Gold Standard, in my case ABVD. When I was treated, trials were investigating Stanford V, the fifth attempt by a team at Stanford to improve on the existing treatment regime. It was similarly effective at curing Hodgkins, but the side effects were, if anything, worse, so, no dice.
For cars that "Gold Standard" in the US is basically every adult except the very poor and the blind. If an AI can do better than the Gold Standard, even if it's not as good as you'd like, it's an improvement.