ok, that's good. I have known they could reach about 8, but I never knew anyonepersonally that had them that old.
Reptiles are very different from mammals. They do not live like we do. More food and better, more "favorable" conditions might not work for them, in all situations. They're variable - they change with their environmental conditions. Mammals are more stable, but with a higher energy cost.
While we may view a chameleon's life as being "better" if it lives longer, that is not necessarily a good indicator of "success" for the animal.
A female chameleon thatlays huge clutches over a short life but has more offspring survive, despite her short life, is more "successful" than a long lived female with fewer living decendants. It's relative.
When we see these animals in the wild, they go all out very quickly. they live fast, die young. We can artificially alter things to suite OUR needs.
We want more babies? Simple - feed them an unnnaturally large amount of food and supplementation.
Want calm, gentle and non-aggressive animals - a better "pet"? Breed for animals that are so - they'd not get far in nature...
Want longer lived animals? Keep temps lower, where applicable, and keep the animla healthy, but hungry. They may not have the energy or activity, as awild animal, but they'll develop fewer eggs, wear out slower, and livelonger.