Meanwhile, many people don’t send personal emails anymore and people have switched to a variety of chat apps instead. And a lot of businesses use chat internally, such as Slack.

It’s mostly business use that’s keeping email alive, either business-to-consumer or business-to-business.

Yeah, this whole argument falls down when email is for junk mail, sending files, and password resets, and 6 digit codes. It's by every measure a failure by "product released after 2000" standards.