I own a recumbent trike and have just ordered a Dahon Speed8. I would not expected either to become popular here in Utah in the near future. The majority of cyclists that I see on the road are young males and second young females. There is a social status that goes with their bike. It is having a "right" bike that would seem most important among those that ride a lot.
Probably most bikes in Utah are sitting in someone's garage rarely used. They drive to the nearest bike shop or box store, and pick from what's available. As floor space is limited, these stores are unlikely to have a folder, recumbent or trike. Thrown-back, one-speed, comfort bikes seem to be in greater favor.
The exception here seems to be folks that buy a folder to take on a boat or camping vehicle, both niche markets.
I went into the local bike store that sells Specialized as asked if they would carry the Specialized folder. They had never heard of it and could not even find it in their catalog.
Out in the middle of the country, we are not near any tipping points that I can see.
Regards,
Gary