I don't live in California and the amount of electric scooters I've suddenly seen out of nowhere is crazy. It might be a fad, but unlike you, I'm more like 30% thinking it is a fad vs 100%.
My reasoning:
* Batteries have gotten better than even the basic Segway days
* The scooters are portable. You can fold them and take them in to your dorm, apartment, etc, preventing theft. A lot of work places won't complain about you charging them at work either
* The entry level price is so much lower. I never saw a casual person on a Segway, but I see casual people on the electric scooter bandwagon already
* There is also a large subset of folks that had Razor scooters. I wasn't part of that, but I can understand them being more willing to adopt if they had previously used unpowered scooters.
* Running in to someone might be a problem on San Francisco sidewalks, but it isn't on, say, ISU's sidewalks.