The above situation is acting like a pseudo-2nd-gen email standard that's evolving in slow motion (without us officially calling it "gen v2.0"). Those email policy changes will be adopted because big cloud email providers like Gmail and Yahoo have a massive influence on the entire email landscape.
Therefore, a new hypothetical "MX2" standard that was more coherent with better authentication, anti-spam, and anti-phishing features could be promoted by a consortium of Google/Microsoft/Yahoo/Apple. The smaller players like Fastmail, ProtonMail, Mailchimp, Sendgrid, etc and most everyone else would all have to follow the cloud email providers' lead because everybody wants to be able to send email to them.
A solution that is 100% interoperable with the existing widely deployed solution but also offers substantial advantages can have good chances to coexist with the old solution for years if not decades, supplanting it only slowly.
Examples of success: monochrome TV -> color TV, landline phones -> mobile phones, the Windows 3.x -> Windows 9x -> Windows NT/2k/XP transition.
Email has a really well-working transport layer. The UX layer can see some innovation while staying compatible.
I found your link interesting and informative. I'm curious if you have any specific comments on this quote from the story:
> From there, the email services which implement MX2 would publish a public date, on which all messages sent to them by the old MX record, will be automatically sent to Junk. If just Microsoft and Google alone agreed on such a date, that would be 40% of global email traffic.
Do you think this change wouldn't be enough? If so, why not?
MX records don't send messages. Assuming that “sent to them via SMTP” is meant… well, moving all messages to ‘junk’ isn't a good idea: it needs to be restricted to messages sent on or after that time. But why not just respond with “554 No SMTP service here” on opening the connection?
https://en.m.wikipedia.org/wiki/Lindy_effect