Interesting perspective.

Strength (moreover, nervous system activation and stimulation) seems indeed to play a very important factor. Especially since the majority of people slack down as they grow older. Retirement and environment has a big role in this I dare the state.

Nevertheless, it's just part of a whole.

Think about willpower and incentive to live longer..

And there's much more under need the hood. We are all different types of batteries if you will.