Make junk mail and spam e-mail illegal to start with. Then start doing something about regulating advertising. In an ideal world intrusive advertising would be banned and we'd have to go looking for ads to find them instead of them constantly demanding that we pay attention to them. But that'd entirely blow up Google's whole business model.
CAN-SPAM[0] does exactly that for US businesses. Any email from a US business that is for advertisement or otherwise promotional (as distinct from transactional[1]) then it:
* Must not have false or misleading from/to/reply-to
* Must not have a deceptive subject
* Must be labeled an ad
* Must include a valid physical postal address
* Must have a clear and conspicuous[2] way to opt-out
* Must have a working opt-out process within 10 business days of the user opting-out
* Must follow all these rules, even if the business contracts out their email marketing
Obviously, fly-by-night businesses and scams aren't going to follow these rules, but by-and-large all legitimate businesses do because each individual email that violates this rule can incur a $40,000+ fine
The FTC has a site[3] for reporting fraud violations, and CAN-SPAM violations fall under the "something else" category in the generic fraud violation report form according to the FTC's FAQ[4]
[0] https://www.ftc.gov/tips-advice/business-center/guidance/can...
[1] i.e. it's not to inform you a something happened in the app/site e.g. you have a notification or some action you initiated has completed
[2] in practice, a link with text "Unsubscribe" at the bottom of the email is sufficient.