Somebody in his position (major crew chief, maxed out seniority) would've been making about 120k real dollars, plus his defined benefit retirement, plus flight benefits for him and family, for the past few decades. He spent his time off volunteering to fix museum aircraft so we can say he really really loved the work.

It seems like this guy just truly loved his work. It's ok to be inspired by his passion rather than immediately turning to the most cynical explanation for his long tenure.

retirement doesn't suit everyone

Or, you know, some people like their fucking jobs. Not everything needs to be some min-max'ed income thing - sometimes people do what they love, as utterly mind-blowing and completely incomprehensible as that apparently is to the folks raised on social media.

Its a pretty classic orphan crushing machine example

https://knowyourmeme.com/memes/orphan-crushing-machine