[RESPONSE] All good points.
Re GDPR, I agree. Govs would need to make it very clear that this would be worth it for them—or better, straight pay for it themselves.

Opt out would already be 10x better than opt in. Mandatory → only govs can make it so.

Re gathering data, based on your comments and bio I’ll assume you’re mostly US-centric. I am not an expert on this topic, but my understanding in this topic is that the main issue is not the gov doing illegal things, but rather congress approving of them. The fact that the Patriot Act is still in effect—and just extended a few weeks ago—is the problem. In the US—as in most Western countries—the rule of law is still valid. If a law says you can or can’t do something, the gov must abide by it.

If they didn’t want to respect the law, they could just buy that data online and cross it with what the IRS knows about you anyways.