Why are you assuming it will be used nefariously to price gouge? What if an air-plane taxi startup bought the data and offered you a ticket for cheaper than a normal airline ticket?
Then someone else would be price-gouged. No company is putting effort into harvesting or mining personal data without an expectation of ROI, and that comes by increasing revenue and decreasing costs. Perhaps costs would go down for some individuals, but there would be an increase in others’ costs to more than compensate.
The economy is not zero-sum. If you're getting offered airplane tickets for cheaper than what everyone paid, it's probably because the airline has extra seats available on the plane that would otherwise go unused. No airline would bump a passenger paying a higher fare in favor of a passenger paying a lower fare (barring PR disasters and such) - they'd be strictly losing money on that deal.
Offering an unused seat for less money because they have knowledge that you would buy it at a discount price makes everybody strictly better off - you gain a discount vacation at a price you otherwise couldn't get, they sell a seat that would they would otherwise waste, and the data broker who arranges the transaction takes a cut of the value generated by this transaction.
If you operate on the assumption that it's immortal if any profit isn't perfectly distributed according to your own personal sense of how much each person deserves to pay, you can't have a functioning market. Any system with non-zero overhead can't possibly price things purely on a cost+% basis.
