I believe the majority of trike owners fall into 2 classes.
1) Those folks who want to ride - but have no business being on two wheels. Some of them have never learned to ride a bike or motorcycle, others just aren't very coordinated.
2) Those folks who have physical issues. Some of them can be injuries, some can be age related issues of not being able to hold up a 700 pound motorcycle, passenger and luggage. I have a friend that was in a car accident and it screwed up his inner ear and balance....and he no longer has the ability to balance a motorcycle. I have another friend who was an avid rider - but he has circulation problems and the blood flow to his legs is horrible, and he has switched over to a trike so he can continue to ride.
It is all good.....long as you can keep riding!