I can tell you for sure I cared much less about the job where I wasn't getting paid as much. I would never answer an after work call or go out of my way to follow up organizational or systemic issues. For me working overtime is part of the package when I get paid loads more.
I've tended to think this way, but it's all relative. Plenty of people who've never had a $50k job will treat the $100k job as the baseline/minimum, and wouldn't ever think of going the extra mile like you do. For you (and me?) - yeah, you're paying "a lot", I'll make sure I do a bit extra/more when needed. But if you've never had less, that $100k is your bottom, and you might only consider doing 'extra' for a $200k job.