Just back from the Mickey Rourke/Jerry Lewis film festival and I did NOT get my talking points fax from GPTB HQ, so I'll have to wag it: I think there are significant large-scale cultural forces in play here.
You have the urban (and self styled urbane) folks who get a bit sniffy around anything so "mechanical" as a motorcycle. But it appears that more than just a few will do scooters. After all, they don't look so mechanical. If you ever have read Peter Egan's R&T stuff, you've seen him address this within the frame of old sports cars.
Then there is the fact that motorcycles are "complicated" and "risky". Well, there goes half of everybody if not more.
Reminds me of my other passion, high quality audio. If so many people love music, why don't more folks take quality reproduction of music more seriously? Why do ALL rack systems, boomboxes and the like sssuuuuuuccccckkkkk? (yes, I have a Pod and I use Apple Lossless only) Too mechanical, too complicated & audio buffs behave so as to exclude those not in the know (and, I think as do we motorcyclists do to an extent).
Finally, look around at your own family, friends and neighbors. Think about how many are mechanical donks. How many can't fix a leaky faucet? How many can't do a simple weekend warrior home improvement project or even give a cogent description of what they want to a handyman contractor?
Sorry, I think we'll always be a fairly small minority.
Hope I'm totally wrong.