[stinos]

the very basic trick of balancing the bike

Which is exactly the point the OP makes to that sentence as if we never stopped biking I think. At the least I'd say it's worded incorrectly. Sure your brain remembers the key part of how to do it, but the finer motor skills, balancing in hard situations etc don't just come back from one instance to the next and take extra practice.

[coldtea]

I don't think anyone seriously says that e.g. a biker doing hard mountain bike rides or bicycle stunts etc will be as good after a 10 year hiatus in which he never touched a bike.

[jplayer01]

Bike riding isn't special. Like every skill you learn, your proficiency will suffer if you don't practice it. That doesn't mean you will entirely forget how to apply that skill, even if lack of practice means you've lost proficiency.