Nice video, but he seems to be reading too much into it: “knowledge does not equal understanding”? What’s really going on is that you need “muscle memory” (otherwise and probably more correctly known as motor learning – learning to do something physical subconsciously) to ride a bike, as conscious thought isn’t fast enough. It’s all part of the standard repetition of skills to perfect sports stuff.
Having learnt to ride a unicycle at 40+, I always point out that it’s actually a lot simpler and easier to ride a uni than it is to run – the difference is that we learn to run when we’re 1 or 2 (and fall over a lot in the process) and have no conscious memory of it being difficult. Riding a bike is a similar thing – most of us learned when we were young, and most of our kids are learning even younger, and will have no memory of not being able to ride. As is pointed out in the video, young kids also pick up something different like this a lot quicker – as a older unicyclist it very soon becomes obvious that kids who learn can pick up skills in a few weeks which I’ll never get.
Having said that, I’m sure I could learn to ride that bike in a lot less than 8 months. I’ve tried one a couple of times, and whilst I’ve not successfully ridden, I’m fairly sure that the easy way to learn is the same way a lot of us teach our kids to ride normal bikes, by ignoring the pedals and scooting on the floor. Managed to go a few metres that way, and I doubt it would take that long to get going (but there are more fun things to do, will be clogging up the garage with one of these before I think about getting a backwards steerer).