If that's true (your statement, not mine), this just means that compensation fast fast-food employees get is completely fair.
Sometimes people are simply forced to take jobs that are not adequately compensated.
Does it matter if a lot of folks have different definitions of gravity?
In the most general sense of "market", this is not wrong. However, you're talking from the point of view of a rather specific market theory. That market theory is not a fundamental force, it's just one of many ways of doing things.
It also has a very narrow definition of "fair", which makes sense within its own world, but I would argue is not generalizable outside of that world.
market, noun, often attributive
mar· ket | \ ˈmär-kət \
Definition of market (Entry 1 of 2)
1. a(1) : a meeting together of people for the purpose of trade by private purchase and sale and usually not by auction (2) : the people assembled at such a meeting
b(1) : a public place where a market is held especially : a place where provisions are sold at wholesale a farmers' market (2) : a retail establishment usually of a specified kind a fish market
2. archaic : the act or an instance of buying and selling
3. : the rate or price offered for a commodity or security
4. a(1) : a geographic area of demand for commodities or services (2) : a specified category of potential buyers the youth market
b : the course of commercial activity by which the exchange of commodities is effected : extent of demand the market is dull
c(1) : an opportunity for selling
(2) : the available supply of or potential demand for specified goods or services the labor market
d : the area of economic activity in which buyers and sellers come together and the forces of supply and demand affect prices
Read David Greaber.
There are circumstances outside of the price which affect the fairness of the price.