I think you underestimate the significance of the term polymath. Polymaths don't just read about a lot of topics, they produce in a lot of topics. Brilliant minds like Da Vinci who painted, sculpted, wrote, experimented, philosophized.

Being a polymath doesn't mean you find lots of topics interesting, it means you significantly influence multiple very broad and diverse fields of knowledge. You write papers on nanotechnology, cured cancer, wrote, starred in and directed a blockbuster movie.

You also overvalue the term hacker. I can't tell you how many people I meet who think they are a hacker because they can get a Drupal site up and running or write a blog. I had a boss one time who was so happy that he had finally gotten back into coding. I said, "What'd you do?" He said, "I changed the HTML on the login form!" Ugh.

So, "hacker" is not synonymous with polymath. Hacking is just one small field of knowledge that may be a part of a polymath's repertoire.