Back in the day an absolutely minuscule portion of humanity read blogs.
Technology Connections has 3 million subscribers. That's over 10x the number of people reading the most popular blogs in the world circa 2010[1]. And Technology Connections is only a moderately popular channel. If you look at the bigger channels like Mark Rober it is more like 350x.
What actually happened was that the first generation of text-loving online people were eventually outnumbered by subsequent waves of "migration" by people who don't like text and prefer images and (especially) video.
It was just replaced by a better product as the online audience expanded to become more representative of real people. Nothing stops people from writing blogs today. They'll probably even get roughly the same (small) number of readers that blogs pulled back in 2010.
[1]: https://content.time.com/time/specials/packages/completelist...