Two points:

(1) I haven't seen this article mentioned here:

https://gravityandlevity.wordpress.com/2009/07/08/your-body-...

I am not sure if the article addressed this model in particular, but I found it compelling.

(2) It occurred to me that most of us don't fear death as much as becoming increasingly useless as we become older due to ill health and physical weakness.

It would be not much fun living to be 200 if the last 120 years were spent in a bed or wheelchair.

So what we want is not to increase the lifespan but to prolong the amount of time we can spend in relatively physically prime condition. I am sure this is not an original thought, but something worth mentioning.