> Price discrimination (charging people more who can afford more) can be good for low-income customers.

Unfortunately it doesn't work out that way. Consider banks, for example. As a relatively wealthy person, I don't pay fees for practically anything. On the contrary, banks pay me in the form of new-account signup bonuses, interest-bearing checking accounts, ATM fee reimbursements, etc.

Poorer bank customers, on the other hand, are continuously getting nickeled-and-dimed by banks in the form of monthly account fees, foreign ATM fees, NSF charges, etc.