Suppose you run a fleet of a thousand machines. They all autotune. They are, lets say, serving cached video, or something.
You notice that your aggregate error rate been drifting upwards since using bpftune. It turns out, in reality, there is some complex interaction between the tuning and your routers, or your TOR switches, or whatever - there is feedback that causes oscillations in a tuned value, swinging between too high and too low.
Can you see how this is not a matter of simple deduction and rollbacks?
This scenario is plausible. Autotuning generally has issues with feedback, since the overall system lacks control theoretic structure. And the premise here is that you use this to tune a large number of machines where individual admin is infeasible.