Comment: ROI depends on investment as well as return (Score 1) 139
The original material talked about salaries and job titles; it didn't say how much investment it took to develop the skills to get those titles. Some of those skills are things you can add quickly; others take a long time or access to appropriate work environments. (For instance, learning PHP is quick, and Ruby on Rails isn't that hard either. But while you can learn SQL and MySQL pretty quickly, becoming a DBA really needs access to real-world databases and workloads that you're involved in administering.)