I'm with you. But also from that video is the correlation where the son has only been riding for 3 years whereas the guy has been riding for e.g. 30 years.

I'm interested in what would the difference be for them to alter a learned skill if they'd been practicing for the same amount of time (so that it's less set in stone)? I'm certain his son would have still been an order of magnitude or 2 faster, but probably quite a bit less than the original number.

I remember a few years ago I learned that I had been tying my shoes wrong my whole life (tying a granny knot instead), so my shoelaces would come loose at least once per day. It took me a few weeks of practice to manually think through the hand movements to make the new know before my brain got used to just doing it without thinking about it.

I'd imagine that as a child it should have been at least 10x easier to re-learn.