Re: is anyone also finding a lack of interest?
I am sure there are a large number of reasons behind the seemingly waning interest, and likely varies from place to place.
I have definitely seen a rise in the used/beaten/broken china girls for sale on the Austin area craigslist and far fewer $500 - $900 new builds. My theory on our area is that people thought they were a super cool alternative to cheap chinese 50cc scooters and bought them for commuting duties. Then when the inevitable mechanical issues arose and the rose colored glasses came off, the reality was that a lot of China Girl builds take a good amount of preventative maintenance to keep them running.
For most people in our area, a new 50cc or used 150cc chinese scooter will cost about the same as buying a pre-built China Girl (or even a self build with upgrades) and will end up being a better commuter for those not inclined for wrenching.
And there is also a lot of adoption to nearly silent electrics. I have gone to an electric build myself and love it!