Do many people use Gutenberg block themes?

What I see (and use myself) is enabling the classic editor, using Advanced Custom Fields Pro with a Flexible Layout. Then implementing a module system for use across different post types and pages. Usually built within a custom theme. Otherwise, I also see page builders such as Elementor & Divi.

I do. I was not into WordPress until recently. Gutenberg has been very easy to get started versus writing a lot PHP. While there are still annoyances, I have managed to work around. Maybe my projects have not been that complicated, but I feel like the Gutenberg team is heading the right way.