My experience is people generally do different things when it's out of interest. More going deep on whatever their passion is, less of everything else. So you get ugly sites with interesting essays, or beautiful data visualization but no text for search engines to use to know to send people to the page. I really liked https://srconstantin.wordpress.com/2019/07/20/the-costs-of-r... on this.

I also think (though don't have the numbers) that there are many more hobby sites now than there were in, say, 1995, because the whole web is so much bigger. They're just far smaller portion of what you're likely to encounter.