I wonder how much of that is internal vs external. For example, if taller people have higher self confidence / belief that they should earn more they might be m

I wonder how much of that is internal vs external. For example, if taller people have higher self confidence / belief that they should earn more they might be more likely to ask for a raise, move to a higher paying job, or start their own company. The external side could be something like, taller people are more intimidating or likeable and thus have easier time getting what they asked for.