I’m not sure I trust USPS to get all of the ins/outs of email spam/security/ux right. Google has spent a lot of resources to get Gmail to where it is today, starting from scratch (or OSS) seems like a big ask.

Maybe we just ask for an open authentication system instead? Leave the email part to someone else… and maybe the open authentication can plug a crypto app/email/phone backend for recovery once it is setup. Heck, given that’s it’s the USPS, they will probably offer a snail-mail recovery option (for better or worse.)