I always wonder what and how it’s like. How big is the difference compared to other categories like HTML templates (in terms of earnings). How the authors handle support and annoying buyers (the ones who ask for support without reading the documentation). Did it change your life? Can you say you made the right decision on being a theme author?
There are some people who won’t read the documentation regardless of what you make.
As I haven’t released my first Wordpress theme yet (I’m working on it) I’m only going to comment on what i’ve reserved.
Wordpress earnings are significantly higher than regular themes only because they usually cost over double and they are one of the most popular categories on Envato. So it’s safe to say Wordpress themes will make you more money than regular themes (Not saying there isn’t money to be made in regular themes).