[edc117]

Sorry, but disagree. I guarantee you many passionate software developers are working on their development skills - learning new frameworks, building personal projects that carry into their day to day work, and yes, sometimes even developing something the company can use 'for fun'. Are there developers that don't? Sure, same as there are sales people that don't.

Edit: As another post says, it's because sales people are only one step removed from the revenue-gaining process - they are often directly responsible for closing a sale, so they can easily claim credit.