As long as the majority of people are relying on emails (regardless of the use case), it ain't dead.
Even if you don't use it to communicate to other people, you're still relying on it (for example, you forgot some random password), making it impossible to get rid of.
Nothing replaced it, and nothing will replace it for the next decade. Not all people on the Internet have a Facebook account where they let anyone in their friends list, and not all people on the Internet have a phone number that they are willing to give publically (for WhatsApp/Signal/any-mobile-first-IM-solution).
If you try reaching me online, you won't find my Facebook account on a search engine (nor on Facebook, unless we have some friends in common), and you won't find my phone number easily (unless you already have me on Facebook as a friend). You'll find my email address easily though, and that's why it'll remain relevant.
Same could be said for pretty much every GitHub user (that's why email addresses are right on your profile by default), every academic that has his own website, most of HN users (just take a peak at random profiles) etc.
