It's not just about precision of position, it's about precision of timing. Intuitively knowing what to do, precisely when it's appropriate to do so, as a result of combining numerous sensory details. If you know exact details about the metal you're welding and the machine you're welding with, you could program that in, but human bodies are too varied, surgery is damn hard. I'm bullish on AI these days and I still say the actual hands-on part of a majority of surgical procedures is a ways off from automation. Maybe one day, with enough data from tele-surgical procedures, you might be able to get that intuition into an AI. But I think we'll sooner be able to generate feature length movies from whole cloth with nothing but a one-sentence prompt than have most surgeries have the important moment-to-moment hands-on decision-making done by machine.