Google would only do that if Microsoft and maybe some other big free email providers would do it as well. It would not be for monetization, but to start to tie

Google would only do that if Microsoft and maybe some other big free email providers would do it as well. It would not be for monetization, but to start to tie addresses to well known identities. A coordinated action from the biggest providers. Addresses like htfan199100@gmail.com (the Managing Director and Head of Investment Banking of the Emirates Investment Bank in Dubai who sent me an email with my public IP as the email subject) would disappear, since paying 20€/year for such a purpose would likely not be lucrative anymore. They'd move to some other shady domains which could easily be blacklisted.