[RC-Monster Mike]

Thanks, Rene(Serum).
The motor doesn't really "need" rear support, and it wouldn't be super easy to implement, as it would have to adjust for gear mesh concurrently with the front of the motor on the mount upright. Personally, I think the complexity is not worth the benefit - the mount itself is quite rigid and, barring catastrophe or extreme abuse, won't need support at the rear of the motor to be effective.