Re: Email is absolutely broken...
Email protocols are real garbage and drastically need a complete overhaul for the modern world. There is no reason why we can't, but nobody has yet posited a standard that would work.
We need a decentralised, encrypted end-to-end, certificate-verified system where even if GMail are receiving your email for you from the wider net, they AREN'T able to read your messages. Then we need an "opt-in" requirement where you can select who you want to receive emails from (which will come about accepting THEIR certificate).
Then we can start thinking about the more complex solutions of email forwarding etc. or just change the system entirely. You can then remove all the SPF, rDNS, greylisting, etc. stuff.
However you *won't* escape a dependence on DNS though if you have half a brain you'll insist on the relevant records being provided over DNSSEC.
Until we literally throw SMTP, IMAP and POP out permanently, we can't progress on email security.