Didn't know anyone could draw worse than myself! lol
I suspect because moving them to the top of the guitar would put them in the way of most players' forearms. It would also require a larger movement away from playing position any time one needs to adjust controls.
It also means that you can't set your hand there. Some people like it because it's easier to get to the controls (that's why Hendrix did it) but it also makes it easier to hit them on accident.
Then your arm interferes with them. People knock guitars that don't have contouring to the top, and complain when bridges dig into their palm.......add in knobs that dig into the forearm and that could be the least ergonomic guitar out there.