It's 100% true that a national economy's Medium of Labour Exchange "currency" is solely backed by what it's own people see as the Labour Value that it pays for. So a janitor makes $1200 an auto worker or brick layer $3,000 a doctor $8,000 and a banker's hard work is rewarded with $20-75,000 a week, and what those amounts buy makes the janitor the poor dude. the amount of money that the private Federal Reserve Gold-Pharaoh's printing company counterfeits to pass out to themselves to fix markets with and rent out to the governments that they own for the taxes they can extort is largely irrelevant until they start inflating everything with interest rates again.
Before 1971, bankers are no different than other business, they have to operate and manage the risk (some of the loaned money will not be recoverable), they have to acquire the gold with real valued assets so that they can expand the money supply. So the income difference you described are related to the different level of komplexity of the skillset, that is fair. If the bankers becomes too profitable, there will be more private banks to compete
But after 1971, it becomes a scam, new money do not need to be backed by gold. The banking business suddenly become super profitable due to endless new money from the lender of the last resort, thus they started many bubbles with their printed money. And these bubbles greatly changed the definition of a good job: A well paid job is no longer related to the amount of effort and skill required, it is related to how close you are to the central bank and its easy money. Some of the entrepreneurs even told me that it is not important to make a profit but important to expand the sale scale so that you can get more loans from the banks
Again, all these are based on people's consensus of how much a dollar worth, not based on supply and demand
