> even talking about utility assumes the price someone is willing to pay reflects their utility gain
It does. It reflects their utility gain relative to the utility they gain by spending that money somewhere else, or just keeping the money for the future. People not made of straw do not generally believe that the price someone is willing to pay reflects somebody else's utility. Nor are they unaware of the tendency for marginal utility to decrease.
It does. It reflects their utility gain relative to the utility they gain by spending that money somewhere else, or just keeping the money for the future. People not made of straw do not generally believe that the price someone is willing to pay reflects somebody else's utility. Nor are they unaware of the tendency for marginal utility to decrease.