And what are most of those websites and web apps used for?

To try, very hard, to keep the user on the site as long as possible, to shove as many ads as possible in front of their face.

Consider the opportunity costs imposed on everyone else as a result of tech.

Also, if "everyone" in your social circle can build websites with React, you need to get outside your bubble more - because I work in tech, and I don't know a single person who could build a website in React. Myself included. I'm happy with a Jekyll rendering pipeline these days.

We've done some neat stuff. I won't argue. But I also think that the current state of (suitable handwave) "tech" is long past the point of diminishing returns for most people, and well into negative returns.