Jerry, somehow I feel you are killing your credibility by exaggerating too many things. Doing 40mph on a bike is possible, but nobody can do 40mph for the whole day as a Ruckus can.
My personal experience with a 50cc is that you can do many things with it, and the bigger the city - hence, more lower speed limit roads - the most useful it gets. Hondas - C70s, Ruckus and Metropolitans have all been used to cross the U.S., and so I strongly believe that there's a big element of mind over matter. If you come from a car, got used to the acceleration of a big car, then you'll find a 50cc to be very weak and inadequate.
I came from being a cyclist to a scooter rider. So I know that a compromise can definitely be found somewhere.