What is this actually about? What should you be getting out of this - what should I?

This article goes into some possibilities for previous speculation that there's a literal physical change around 44-50, one as notable as puberty if not quite so obvious.

https://www.theatlantic.com/magazine/archive/2019/07/work-peak-professional-decline/590650/

 

Denis Leary released "No Cure for Cancer in 1993. It's in some ways a quintessential Baby Boomer view of the world, such as how his first memory starts "with a shooting on November 22 1963 and ends a few days later after a wake, a funeral, and another shooting." 

https://en.wikipedia.org/wiki/No_Cure_for_Cancer

The title, he notes in the book of the stage play of the DVD of the film, is a swipe at Baby Boomers, who spent so much time in hedonistic pursuits that the big items - like a cure for cancer - were never as important as they should have been. 

Although I would also point out that I know several cancer survivors, and that even if a single absolute eternal cure for cancer hasn't been found, the Boom generation and its fellow cohorts are not doing as bad as it seemed 30 years ago, or so.