We probably all have anecdotal evidence here, but my father is a perfect example of being no longer employed and a ton of stuff declining. Yes, cognitively, but a lot of health. We're talking not just your "career". He was a commercial real estate agent. But in his 80s he was working at Menards as a greeter and stocker. And it kept him busy. Getting out of the house. Figuring things out. Meeting and talking to people…
Saw similar with my grandmothers. One had a busy social live and volunteer schedule for 20+ years, the other.. did not. A reminder that you cannot simply retire FROM something (work, commuting, etc) but must retire TO something (hobbies, social life, second career, volunteering, etc). There's always more opportunities in the community than there are volunteers, so look around.
Yeah, my guess is that someone retiring early to pursue their hobbies and interests is going to be much better off than a blue collar worker made redundant or disabled in his 50's. I always see these sort of studies used to slam the idea of FIRE, but I very much have my doubts that these findings apply equally to everyone.