That's not a fair continuation of the thought, is it? Even balancing on an entire rotating log isn't trivial. The problem here is standing on a small patch of surface that is moving under you.

The required insight for the bicycle is that, counterintuitively, a rolling wheel doesn't fall to either side. The axles, fork, frame, and seat are 'just' the elaborate way of mounting yourself to those rotating discs so that you can move along with them while sitting still.