It is interesting that you picked "riding a bike". If anything, there has been a generation leap in how fast children can learn to ride a bike. Get them started on a Strider bike with no pedals. Once the child is large enough to ride a bike, they can teach themselves in about one or two days. (Numerous parents in the 2020s have confirmed this pattern to me.) Something about the Strider bike teaches them a lot about how to ride a (pedal) bike when the day arrives. When I grew up, I didn't have a Strider bike (I'm not sure they existed where I lived). Learning to ride a bike was tough and took a lot of practice with my father.