[Eisenstein]

Thought experiment: you can ride a bike. You can see other people ride bikes. Some portion of people get on a bike and fall off, then claim that bikes are not useful for transportation. Specify what skill they are lacking without saying 'ability to ride a bike'.

[quotemstr]

For a bike? Balance, fine motor control, proprioception, or even motivation. You can always break it down.

[Eisenstein]

Knowing those things won't help them acquire the skill. What will help them be able to ride a bike is practicing trying to riding a bike until they can do it.