I now buy flights direct from airlines because of the dirty tricks of resellers. They've been terrible at sorting out missed connections (please get a paper document in person from the middle-of-nowhere stopover airport to prove it was their fault, and not going to refund legs on a 2nd airline at all) and do dirty tricks like not actually booking your ticket when you pay but waiting till they expect to get it for a lower price, which might mean not getting it at all. I know airlines overbook too but it's one less reason for an already stressful trip to go wrong.

Custom pricing feels like buying from a shopkeeper with no price stickers. You expect to get charged according to what he judges you can afford. It removes the value of being able to rely on all the other customers to collectively decide if the price is fair or not. That means every customer has to individually evaluate every price which is a massive waste of effort.