They'd make the same money per flight if 10 people paid $1 or if 1 person paid $10. They just want to keep it greedy.
Just the opposite, in fact - they want to keep it "fair" and that's the whole problem. Reality is you get what you pay for. This is true for loads of gravel to bandwidth.
But Americans are programmed to demand "fairness" and "equality" in all things and revolt when given pricing tiers that reflect reality. The most workable option, at present, would probably be to have SSID's for "First Class", "Business Class", and "Steerage", because those discrimination levels currently exist, and price accordingly, though there's no rational reason for somebody to not be able to prefer steerage seating and first-class routing, or vice-versa.
"Fairness" is a dangerous fantasy.