Went I had the store at first it was still mini bikes but in mid 1972 the Mini Cycle market just exploded I took on Indian first and then Rupp and Alsport had the Steen with the ace 100 Hodaka engine . And all the mini bike sales just failed.
As for trikes there are Two kinds first is the ATC like the Honda you sit on top and straddle the engine . And the other style is the ATV The Dunecycle,Tri-Sport, Sperry Rand, Dune Gote, Tri-Cat Mud Bug Montgomery Ward T-555 these all were ATV's.
When the Government stopped the importing of the ATC's like the Honda, Yamaha, Kawasaki and any Trike of this style could not be sold as a new vehicle it was a result of a very poor safety record and improper age groups riding and getting hurt. If the industry don't watch out the Quads safety record may suffer the same fate.
Conclusion if you love to trike go for it . Steve