I mean the bastard lived till 83. Why? What could be possibly have been holding on for? Other than wasting taxpayer dollars, I don't understamd why he wasn't executed. Of course, this is all from before my time so my grasp on the reality of the situation is foggy at best.
However, I do have a crazy theory.
American Horror Story.
This last season glorified the Cult, and heavily Manson is the last few episodes.
The season ended, and no more spoilers, but I think he held on, just to watch Kai succeed.
I would have given up on life after watching that finale too.