That 80/20 rule seems fair, but that Verve is holding him back. Everything about that bike is suited against the type of riding you do. You could probably pick up a lot of speed by switching to a drop bar road bike. I'd assume a lot of the power you're putting down is being wasted because of the upright position, suspension, gearing, heavy wheels and wide tires. So in this case it could be your equipment holding you back, and not you.