Differential pricing is so important to some industries that the market will find a way. If you try to ban it, you'll get more bizarre contortions. One business that uses differential pricing even more than air travel is insurance. We have tried to ban insurance companies from using factors like race in order to meet social goals, but that just drives them to use zip code or anything else they can invent. Insurance companies might argue this isn't differential pricing because what they sell is risk mitigation, and the higher risk you are, the more that should cost.

Of course, airlines could try pricing based on net worth, which is what they really want, but that would create more chaos (and probably be quickly nixed by competition.)

Every year or two, some airline announces it is going to move to simpler pricing. But when there's competition they quickly move back. The public wants the differential pricing. The current airline system has the majority of passengers paying less, and a minority paying quite a bit more, which is what everybody but the minority (corporate flyers) likes most of the time.