I trust you, but still can't see a reason why this thing's prices wouldn't behave the way all high tech mass marketed gadgets prices do.
Not all mass marketed gadgets, with high tech materials or design, decrease in price. Of the ones that do, not all of them decrease in anything like the way computers, VCR's, or DVD's have done. Electric wheelchairs, electric assist devices, motorcycles, mopeds/scooters, telescopes, binoculars, guns, and even high end bicycles have not dropped drastically in price in the past ten years.
In any event, before the inventor can hope for the prices to drop, he's going to have to find some demand for the thing as it is. The comparisons to IBM's misjudgment about personal computers require more than just the fact that this invention is dismissed. They require that the skeptic be wrong.
Yet, the problems with widespread adoption of this scooter as a "people mover" have been mentioned by many posters already. Most of these problems aren't specific to this device, and have been the pitfall of other purported car substitutes. Weather, range, carrying capacity, and discomfort are problems for mopeds, bicycles, and scooters you can fall off of. We have plenty of experience with these other devices. So far, huge numbers of people haven't gotten on them, and city planners are still shy about banning cars. There's no obvious reason to think these new scooters will be different.