Average in a (big) city is skewed by other office jobs. Developers are not the only white collars in town..

> developers have to waste their evenings, weekends and vacations to learn new technologies and you will not even be paid fair for that sacrifice

You can read tech article at work. Not mandatory to work at home to learn new tech, and if you do, it's up to you to be paid for it: change job to match your news skills.