General question - I don't understand why so many static site generates, github, many others, all use templates that won't fill the width of the page. Is using the full width of the page particularly difficult to design for? Or is it an aesthetic decision that template authors feel like having a 20 inch wide monitor with 8 inches of text in the middle flanked by 12 inches of white space is a nice layout? Particularly for code examples it's very frustrating seeing lines wrapped around unnecessarily on a large, wide monitor.

(sorry if this sounds like a rant, actually just genuinely curious).