His right foot IS well ahead of the rubber at the release point.
However, he still drags his toe as if he is desperately trying to to keep his toe on his rubber. If he didn't try to drag his toe, and instead just let his leg and his hips come around like they want to, he might be able to reach a higher velocity.
Granted, this is all sheer speculation. Doing what I say above may completely throw off his balance.
However, I'm not convinced that any pitcher has achieved perfection.