The question is, how does one know one is poor except by relative differences in inventory and consumption? Poverty is the natural condition of man. Property and mutual insurance of it, lift us out of poverty.
THE ORIGIN OF THE CONCEPT ‘POOR’
“poor’ evolved from pre-Latin *pau-paros “producing little; getting little,” a compound from the roots of paucus “little” (from PIE root *pau- (1) “few, little”) and parare “to produce, bring forth” (from PIE root *pere-(1) “to produce, procure”).
In other words, the original meaning of poor in proto indo european (well before the invention of money or money substitutes) was ‘one who produces very little.”
And this remains the cause of poverty. One who produces very little and therefore consumes very little.
The evolution of money requires the production of surpluses that cannot be consumed and can (must) be traded across production groups in order to obtain that which is not self produced.
Barter-price (cattle, chicken, lambs, etc) can function for certain transactions, if those items can serve as a store value (they do).
But money must be portable, have a high weight/volume to value (time savings), be unitary measure and divisible, and universally (within the trade network) liquid (in demand).