well, no one buys em here because 1) obviously not available, but they're not available cuz theres no market for em. Even the cities in the states seem much more built to accommodate cars and are very spread out. getting around is most easily connected by throughways and those require higher speeds an often do not permit small motorcycles.
Couple that with the fact there are no benefits offered to riders of small motorcycles - you still need an mcy endorsement insurance etc -all the motorcycle laws apply- it makes too much sense for people looking in that realm to bump up to something highway capable. Either you keep it stupid small and simple (which winds up being most often a scooter) or get a motorcycle (in which case you get something capable of motorcycle stuff, like a 250)