Also I'm sure somewhere "mobile users" is a metric in a company valuation equation. Pinterest is the worst offender of a mobile app that doesn't need to exist since the web counterpart can do 100% of the job. This being a product that leveraged JavaScript in browser bookmarks to get "pins" without an app or extension.
When Reddit stopped allowing non-email-verified signups and conveniently locked everyone out who did have a non-email legacy account, the writing was on the wall. They didn't even have their own mobile app for years after the "mobile first" rhetoric and guess what... It still grew to the #3 website in the world.