tbh I'm with the zoomers on this one. Work email is 99% junk. Newsletters from every SaaS product we use, "A meeting started", invitations for calendar events that I can just accept ON the calendar, notifications for every transaction on every system ("X posted a comment on Y,") and spam from salespeople, recruiters, etc. And then 1% of it is actionable important stuff that I don't get through Slack.

Email died because of the junk/spam issue. And it's self-fulfilling - when most emails are junk, nobody sends a love-letter or party invitation by email because the recipient probably won't notice it, which in turn lowers the usefulness even further.

If email was a commercial product, the company would have done something about that. Email died because it was an open platform, with nobody to address this systematic issue.