What you are pointing out is an awareness of unfairness, rather than disappointment with rewards. Fakebook don't pay no rewards, so leaving here because @haejin gets 5% of the rewards pool makes no sense from a purely financial standpoint.
Dogs, octopi, and crows have all been shown to be extremely sensitive to fairness, and humans more so.
My own motivation for being here has nothing to do with emuneration, and everything to do with free speech, so I intellectually rationalize the unfairness and consider it irrelevant. That's just me, though.
It is a real psychological harm to be treated unfairly, and people avoid that harm in droves. We are social beings, and reckon society should give us a fair shake. Financially, that's not happening on Steemit, and as you point out, fixing that problem will dramatically improve retention.
Thanks!