Another way to look at it is every exchange is necessarily unequal. Both parties gain else the exchange would not happen. So there is no expected "equality" in exchange.

What Aristotle and Aquinas are saying here is that money is sterile and that lending at interest is theft. You said nobody ever thought that. That's actually what everyone always knew. What you are doing is repeating the trite rationalizations that we grew up with in a time of perversion, under a system built in fraud and theft. Fiat is not just evil because they can print more. It's evil because it is usury. What you are repeating is fiat's justification. The very premise. The magical belief that lending creates value, when it does not. Christ flipped tables over it. Muslims revile it. Jews even know it is evil which is why they are forbidden from doing it to each other. (For some reason they are ok with doing to gentiles.) The Buddha denounced it. Etc. etc. Money is an information system to coordinate work. To charge rent on money is to cheat the game and take it hostage, to trade someone else's labor for none of your own by taking advantage of their need. It is predatory and evil. The best moral minds that the human race have ever produced all agree and have explained it at length. What you are saying is just a perverse rationalization. It's mental gymnastics that we were all indoctrinated with, but it is an evil and predatory view that justifies theft and slavery. Bitcoin was built to destroy this evil. When money is honest, it will be obvious to everyone again.