While what you said may seem logically correct, there are a myriad of privacy protections that corporations are expected to adhere to regarding the information customers entrust to them. One reason for these protections is that the "resolution" you've suggested --- that the customer can simply choose not to use their services --- provides no protections against future-use of information. Say a customer chooses a vendor that sells his information after he ends his service with them. Under your strategy - the customer would have absolutely no recourse since he has no leverage against that vendor. He's already "walked" so to speak - yet they still may have information of value about that customer.

Take another example. A medical facility cannot take customer information about a person with a specific ailment and sell that information to advertisers for the purpose of earning a commission on the sale of those targeted ads. There are laws forbidding how that information is shared.

The following link outlines some of the state and federal laws specific to California, but each state has their own, and the federal laws obviously apply to the entire United States.

http://oag.ca.gov/privacy/privacy-laws