I doubt any social movement toward equal pay without regard to any other factor will ever exist, or could survive long if it did.
Would people still go to college and become doctors, lawyers, engineers and other types of highly educated professionals if there is no pay incentive whatsoever, and they will earn exactly as much as a high school dropout washing dishes?
Yes, I know some people don't do it for the money. But most people consider a "good living" and a salary of six figures or more at least ONE of the reasons they are busting their butt in college to get their terminal degrees (PhD, JD, MD). (In academics called 'terminal' because there is no higher academic degree for the field in question. Of course multiple terminal degrees can be earned; a person can be a PhD, Juris Doctor and Medical Doctor simultaneously.)
Absolutely equal pay for all is roughly equivalent to communism, and communism fails, not necessarily for corruption, but because it lacks incentives for workers to make any effort. They cannot get ahead no matter what they do, so being human, they quickly fall into doing as little as they will be allowed to do and still get paid, and resort to outside-the-system means of actually getting ahead. Black market trading, under-the-table labor and services (perhaps including prostitution or pimping for prostitutes), drug production and sales, gambling, and so on. With organization, these can turn into a mafia.
In America at least a social movement for "equal pay for equal work" already exists, so does a social movement for a "living wage". I agree with both of them, for what its worth. But superhuman people could easily argue that "equal pay for equal work", by extension, means they deserve to be paid double pay for doing the work of two people.