Everyone is always trying to kill email, and it's always because it's a supposed productivity villain and life will be so much easier when we can all live happily in some chat based universe. I've spent enough time in Slack and Teams and their predecessors to know that we should go back before it's too late.
Chat brings you infinite inboxes and no great way to tell which of them is important. Having looked away for a few minutes there are dozens of unread conversations. Some of them are people sharing a photo of their cat. One of them is an emergency requiring immediate attention but good luck finding it without wading through everything.
This brings me to a lack of useful state. I handle email in two quick passes - read everything (and discard anything that doesn't need further attention), deal with anything critical and then at some point go back and mop up the rest. In chat though you just blew past something that needs a response eventually and it fades from your mind as you fight the fire elsewhere. I never miss an email, I often miss a chat.
And good luck finding anything. Maybe a market leader or two will establish dominance for long enough but my experience so far has been lurching from one platform to the next, both professionally and personally, and having a hard time finding that one thing I know should be in there from the end of last year. My Gmail has emails going back to 1996, and yes that's almost a decade before Gmail existed. I can find anything.
On the subject of dominance, the real reason for all of the attempted email homicide is that it's one of the last open systems that everyone still uses. If only email would just die you'll be trapped forever in Messenger and Hangouts.