What I do know is that what we have today is an absolute mess and it's horribly inefficient.
Now I need to charge users before I let them sign up for an account, because if I send them a confirmation mail when they sign up, and then a couple password resets over the years and I've got more than a handful of users, it's going to be real money. Which isn't that hard, but users don't really want to pay $1 to join a forum or whatever.
The bigger problem becomes how do you actually tape a penny to an email? There's a lot of diversity in email providers (even if there's a lot of concentration at the top), and international payment flows are extra fun. Plus, a penny USD is a significant amount of money to people in many less wealthy nations.
And the whole thing is very decentralized, so good luck with adoption.
Misappropriating personal information for unapproved purposes is on the same level as misappropriating credit card numbers for unapproved purchases. Just because an entity has access to information does not mean that they are justified in using that information in any way possible.
Sadly, I immediately realized that if such a law was passed, the major email providers would all implement the opt-in check using a web-based system (as opposed to a fundamentally email-based one, on easily argued "convenience" and "accessibility" and "user experience" grounds), and thus achieve vendor lock-in.
In the end it would amount to another form of implicit censorship through badly managed filters and whatnot.