I don't think they make very much money at all from selling your info. The banks that issue credit cards make most of their money from interest and interchange charges (what the bank charges the merchant for a person using the card - varies from 0-2%)[1]. Rewards are what the pay people to use their card and they hope to make them up with the former methods.

Do you have a reference on how much they make from selling data? Do banks release such info on their annual reports?

[1]https://www.valuepenguin.com/how-do-credit-card-companies-ma...