Perhaps all the repetition is simply to bore our conscious mind into getting out of the picture. There are lots of examples of where “thinking too much” interferes with a well-learned process. Try riding a bike while paying close attention to what you are doing!
It’s arguable whether or not conciousness is involved with learning at all – but if consciousness is not involved, why bother to do drills? Why does drill-work (whether in martial arts, math, etc) help us, when it seems to have little to do with the output?