> The aphorism does not say what it is referring to

In which case it makes no falsifiable claims. If “hard times,” “weak men,” and “strong men” have no stable meaning, the cycle can’t explain anything and can be retrofitted to any narrative. There would be nothing to argue for or against.

That isn’t the case. “Hard times” in this context means the cumulative internal consequences of institutional decay, complacency, and short-termism. Not natural disasters. That’s why your famine example is irrelevant.

> Is there any way to measure this weakness? Is it actually a thing?

Sociological concepts are evaluated by their broad effects, not by a single scalar value. Declining institutional competence, eroded norms, reduced accountability, and loss of collective purpose are both observable and historically recurrent.