Or, rather, plenty of people do. Many of whom are scientists, and all because of the work of scientists (and their cousins, mathematicians and engineers).

It's just much more complicated than "gyroscopes".

It's too bad this has been misreported. The actual science is really interesting. See, most people thought gyroscopes were an essential component of bicycle stability (that, and the rear tire acting as a trailing caster to the steering axis.) That is, if a bike didn't have one or both of those elements, it would never balance.

So they went and tested if a bike could be built that lacked both those features, and still balanced. And they succeeded! Gyroscopic effects and trailing casters are no longer essential to the balance of a bicycle, we know that now.

But that's not the same as "not knowing how a bicycle works." For most bicycles, gyroscopic effects and the trailing rear-tire are quite helpful. But there are other factors at work, too. The arrangement of the bicycle+rider mass, the tilt of the steering axis, and more, all help balance the bike in complex, interconnected ways.

But complex ≠ unknown. "We thought this was critical, but now know it's just very helpful" is not "we have no idea" . . . it's actually "we have a better idea than we did before!" It's nearly the opposite of "we have no idea."

Science knows how bicycles work.