Yep. I've heard similar speculations regarding surgeons before. Fortunately nowadays we can take appropriate measures to compensate (surgeons are highly paid and closely monitored; we take a lot of care that medicine be evidence-based; the rationale behind specific medical interventions is carefully documented and checked multiple times; we require medical professionals to train for longer than any other profession). But note that for most of human history, the interventions performed by almost all medical professionals were literally worse than nothing.