> Years later, when we discover these relics and hop on, it’s as if we never stopped biking.

I'd like to challenge this. Barring scientific evidence to this fact, it is at best an anecdotal evidence, and so I will submit my own anecdote:

I didn't ride a bike for about 10 years. When I started riding again, I definitely felt unsteady for the first few days or weeks compared to my previous riding ability. I was unsteady enough that I thought at the time, "People that say you don't forget how to ride a bike are full of shit."

Granted, my ability to ride came back faster than if I was learning from scratch. It might become a discussion determining different shades of "forget" -- but if we get to that point, then we've conceded the crisp assertion that "we don't forget how to ride a bike".