it’s negligible compared to the load carrying provided by the tire pressure.

My comment was in reply to the “always equal” assertion, which it definitely is not. No doubt, it’s a handy rule of thumb but nobody should walk away thinking it is a hard rule of tire physics.

And that’s the gyroscopic effect, not any of the other things that contribute to bicycle stability but don’t depend on wheel size.

Correlation does not prove causation. You assert that bicycle wheels are big because they have more gyroscopic effects. That is a correlation. I assert in my other comment that small wheels would be swallowed by potholes. That is a causal relationship: the wheel must be bigger to deal with real roads AND is something a smaller wheel cannot handle. It is a fact that a big wheel rolls over protrusions and holes that a small wheel would fall into.