To be fair, that clearly represents a bubble viewpoint of its own and it shows you don't use Twitter. You also may find that a lot of people in your real world social circle do use Twitter but don't publicise it, because they're using aliases and it's not exactly something you mention in most company.
My feed has consistently been full of interesting people doing real things, not those you listed with the exception of authors.
I tried to follow a number of prominent scientists, people doing programming language research, and various other technical topics to experience what you describe. Almost every single one of the people I followed devolved into commenting on politics and niche social issues more so than the technical topics I followed them for, so I gave up. There were only a handful of exceptions like one person that makes commentary about niche literature I enjoy. The format and culture of Twitter seem to inherently discourage thoughtful discussion and amplify politics, rage, and zingers/gotchas.
My feed has consistently been full of interesting people doing real things, not those you listed with the exception of authors.