"The maximum price that people are willing to pay isn't "dependent on" demand, it is demand. In particular, it has nothing to do with supply" What the is maxim

"The maximum price that people are willing to pay isn't "dependent on" demand, it is demand. In particular, it has nothing to do with supply" What the is maximum you willing to pay for breathable air? How much would you be willing to pay if you could not find free air everywhere you went? Demand is not "the maximum price people are willing to pay," it is "the willingness and ability to pay a given price."