I think trikes are quickly evolving into a motorcycle for the non-medical crowd. So many trikes are now on the road that riders are seeing the benefits, particularly those of us who live is hilly, curvy, not-always-paved, areas.
I have tried to explain to many people that my trike only gives up leaning in the curves. Everything else tied to a motorcycle is there for me to enjoy. At the same time, I now find I ride more relaxed. I'm not having to worry at every non-level stop about which foot to put down; whether or not the parking lot is paved, dirt, or gravel; whether I'm balanced and steady enough for my co-rider to mount the trike; and the list goes on.
When I ride my two wheeler, the old brain has to step it up a notch because it has more things to think about and calculate; CONSTANTLY calculating.
Bottom line is more people are beginning to appreciate the non-medical reasons to own a trike.