EVERYONE puts in hours outside the office? No, they do not. I have already told you I have had friends in IT and management and law support and government defense contracting, and I'll add the ones I have known in prison supply, and insurance, and boiler quality assurance and no, they did not. Your only example was a software developer.
Now, if you said I only work 3/4 of the YEAR that an average full time person works, I'd agree. But while I am working, I am working pretty hard.
Now, maybe you didn't. Maybe you were one of those teachers who is out the door the minute the kids are. I've seen those teachers, and I don't really get it, but I know they exist.