[damnesian]

there must be a strong causal link with terrain / the nature of these rides. I live in hilly country so I learned as a kid how to upshift and downshift. 80% of the rides I take would be slow and laborious with a single-speed bike. I'm willing to bet most cheap single-speed bike people (of those who aren't using them out of financial necessity or social conformity) are urban riders who have mostly flat terrain to cover.

[JohnFen]

It was hard for me to believe that most people don't know how to shift gears. Every bicyclist around here learned on a bike with multiple gears and learning to use them was just part of learning to ride a bike.

But your comment gave me clarity. I've lived in very hilly/mountainous areas where having multiple gears on your bike isn't really optional. Not everyone lives in such terrain.

I'm not sure that the bike shops around here even carry single-gear bikes. The closest I remember seeing are three-speed children's bikes. Very interesting peek outside my bubble here.