And I mean here both sacrifice the things you hold dear directly, or indirectly - which for us here is predominantly our careers and places of living.
Exaggerating a little bit to underscore the point: I could likely add years to my QALY lifespan if I moved to countryside, picked up more manual labor that required me to move my whole body, and went hiking in between going to the gym -- but, the things I value are found in cities, the work I like is white-collar, I hate hiking, and I also have people I love to support and lifespan-friendly labor generally doesn't pay enough.
To live a life that's even remotely healthy we have to dedicate a significant amount of the precious spare time we have just to undo some of that damage.
I do not believe we are predisposed to adopt sedentary lifestyles. As kids most of us are very active, but we are taught to be sedentary. Both academically and professionally we are most rewarded for sedentary activities: doing extra coursework, building your resume. Is it any surprise we develop a sedentary lifestyle when such a lifestyle is most rewarded?