You're only thinking of the federal level. There are many levels of government, and local governments from states and counties all the way down to companies contracted by the local dog catcher buy the data mined by advertising companies.

and has been for 30 years - you can buy lists for direct mail of people's name, full addresses, numbers, marriage status, estimated income, etc

But for 30 years you haven't been able to track someone's location on a minute-by-minute basis. Or in real-time in the case of buying data from a cell phone carrier. Plus a lot of other invasive information that hasn't been available until FB, G, and others weaponized the avertising industry.

We're not talking about public data. We're talking about companies selling private data.