I can't think of a more illustrative example than the fact that some magazine companies will keep on sending you magazines even after you cancel and stop paying

I can't think of a more illustrative example than the fact that some magazine companies will keep on sending you magazines even after you cancel and stop paying them, on purpose, so they can still list you as a subscriber. You're worth more as an advertising target than you are as a customer. I'd be willing to bet that their own advertising departments are more interested in increasing the advertising value of the subscribers that do respond than it is in actually selling subscriptions.