The controller market is very saturated. Anything that makes a controller fall out of the consumers spending range, places the controller in a niche section. Therefore that controller will be quickly forgotten about, and end up with a very low sales count.
So if it would be an 8x8 motorized rotary controller with banks, that would be new and could possibly sell well. But adding motorized rotary knobs to existing controller layouts, would make them too expensive for the current controllers market, I think.