I don't think the purpose of the cards is capitalism. We're still going to buy the groceries and I still fall for advertising. This is about privacy.
Those companies put time, effort and money into loyalty cards just to invade your privacy? I don't think so.
I do not think that their shareholders are going to be impressed by an annual report that says, "we spent 10 million dollars to invade the privacy of 100 million customers but we did not make any extra money."
What the investors would be impressed by is when they say, "we spent 10 million dollars on our loyalty card program and earned an extra 100 million dollars in revenue."