I read a biography of the Wright Brothers, which pointed out that they spent quite some time and effort with their gliders, learning how to fly. So they were already skilled pilots before they attempted powered flight. The book suggested that this idea occurred to none of the other airplane inventors.

There might have been a similar problem with the bicycle: Anybody who built the first one had no idea of how to ride it, and lacked the advantages of being six years old, namely closer to the ground and quicker to heal from minor injuries.

What I want to ask: Why are we still waiting so long for the bicycle? There just seem like so many barriers to more widespread adoption.