I was just standing around in my building's garage while my kid practiced riding a bike (with training wheels) and my mind wandered to what it would be like to learn if you could do it fully in virtual reality.
I think a key requirement would be a means of simulating acceleration and balance. In FA!, VR systems use a "floatie" which is a handwavey device that spoofs acceleration in the inner ear.
If we had this, I imagine a set of VR exercises where the degree of tilt of a bike is magnified, or a kid could practice biking in Martian gravity, where you'd fall 3x slower. And you'd never have to take a hard fall! Learning to ride a bike would be so much less scary if you never had to hit the ground to learn how not to.
That made me think of a training center full of two and three year olds learning to ride bikes in VR and then practicing in a padded lot, perhaps with a suspension wire above to catch them and automatic braking on the bikes while they're still learning. That'd be a neat setting for a conversation to take place.