If you are able to create an original theme that offers something new to designers and developers (who are the main customers of premium themes) you can make thousands of dollars in only a couple months. Study the themes with several sales to see what they have in common and incorporate those things into your own theme.
It's also a great opportunity to find customers looking for support and outsourcing.
Really. This is very interesting - it definitely goes against the grain of what other commenter are saying. Don't you think the theme market is over saturated?
If you are able to create an original theme that offers something new to designers and developers (who are the main customers of premium themes) you can make thousands of dollars in only a couple months. Study the themes with several sales to see what they have in common and incorporate those things into your own theme.
It's also a great opportunity to find customers looking for support and outsourcing.