If you start out with a cohort of individuals across the spectrum of ability, over time many of those of lesser ability will self-select out of the pool. It is my experience (oops, see what I did there) that people rarely spend a career doing what they're not very good at. The exceptions inevitably stand out.

So, combining the winnowing of the not-very-apt with the gaining of knowledge through experience, the end result is that you have a preponderance of wise old experienced contributors.

I you are one of the younger inexperienced ones who believe they know better it's likely you'll self-select at some point, secure in your Dunning-Kreuger knowledge, and move to some career in which your high level of competence is valued more.