That and market share. Between 2007 and now, a website could reliably grow as new people got connected to the internet and as internet usage naturally grew. Up till recently, a large proportion of people either didn’t use the internet at all, or had the internet, but didn’t use much. Prior to 2020 I knew lots of friends and family who simply did not own a home computer or maybe had like one laptop for the whole family (and a bunch of phones).
During that era, the attention was all on getting new users in the door. Make a good, cheap/free product, and people will come.
But NOW, most people already are using the internet like 14+ hours a day and have become full netizens. If companies want to keep growing, they can’t rely on new blood, they need to pivot to harvesting more from the people they already have.