This is probably a good criticism if it turns out that the right level of abstraction for most problems is Physics. And it seems like your argument would apply equally well against the idea of human intelligence. Luckily, our minds have developed other abstractions that allow us to solve problems much faster than if we had to simulate them as physics problems. For example, I don't need a physics-level simulation of my friend's brain when I want to predict how they'll react to a gift I'm giving them.