The question is if that cost an individual occurs if they choose not to spend their free time on career-related skills is ethical or good for society.
While by contrast, there are some people who want to kick back and simply collect a pay check, there is a whole segment of people in the middle ground who are hungry to learn, but are stretched so thin that they can’t outside of work — a whole segment that isn’t being catered for, and therefore an opportunity exists to tap into this.
At my university engineers were offered two elective courses in the faculty of arts or sciences. That's not a particularly broad education.
The good news is, you can do it without going back to school. IMO an SE will get little benefit out of going back for another degree. You'll get much more ROI spending your time contributing to OSS projects and making a name for yourself.