[acwan93]

Reminds me of this I heard/read somewhere:

When you're young, you have the energy and time, but no money.

When you're middle-aged, you have the energy and money, but no time.

When you're old, you have the time and money, but no energy.

[nradov]

There's a certain survivorship bias at work, but I see old people around with plenty of energy. I think many use lack of energy as a plausible excuse when they're really just lazy.

https://suereynolds.net/

[d3nj4l]

I wouldn't say lazy. Many people who've been through the grind for 40-50 years just don't have the will to do anything outside of that any more.