So don't say "no astrophysicist understands stellar reactions" because that is false. They understand fully, and can write the model and simulate it to answer any question.
Ditto for bicycles. Just because there is no simple explanation for bicyles does not mean we don't fully understand the physics of bicycles. It just can't be put in English. Only in complex mathematical models.
Cyclists are not exactly the equivalent of "astrophysicists" in this situation though. There are of course physicists who are also cyclists, but basically no cyclist who is not (or isn't very interested in the field) would be able to explain it.
This is probably a case where not being a scientist was an advantage. Turns out they didn't need a simulation or mathematical proof it could work in order to try it.
> Their study shows that there isn’t one simple reason for this phenomenon. A combination of factors, including gyroscopic and caster effects, bicycle geometry, speed, and mass distribution come into play to keep an uncontrolled bicycle upright.
I think we’re saying the same thing. There is no simple physical explanation that humans can intuitively understand, because the interaction of forces is so complex. I’m not claiming that it’s a mystery causing fundamental problems for physics.