> if I recall correctly, the fremens (who had unlimited access to it) were a bloody waring bunch

They were, but not because they had spice. They had spice long before they became a bloody warring bunch. The interplanetary jihad was at the behest of Paul Muad'dib. The Spartan and militant culture that existed before Muad'dib was mostly out of self preservation in the face of a brutal Arrakis environment and colonial oppression.

It's a common misunderstanding that curing aging can be a pill. Aging is a quite loaded word. It means at least, curing cancer, heart disease, Alzheimer's, cell loss, hardening, muscle loss, vision loss... So what an aging cure really looks like is lots and lots of cures because there's lots and lots of causes. The easy way to categorize what needs fixed is: Cells: too many, too few. Junk: inside and outside cells. Mutations: nuclear and mitochondrial. Finally crosslinking.