The problem of interpersonal comparison of utilities seems to bother economists more than philosophers. As already indicated, utility or satisfaction… - Kenneth Arrow

Not only is it possible to devise complete models of the economy on hypotheses other than rationality, but in fact virtually every practical theory of macroeconomics is partly so based. The price- and wage- rigidity elements of Keynesian theory are hard to fit into a rational framework, though some valiant efforts have been made. … But if the Keynesian model is a natural target of criticism by the upholders of universal rationality, it must be added that monetarism is no better. I know of no serious derivation of the demand for money from a rational optimization. … The use of rationality in these arguments is ritualistic, not essential.

This is by no means a "formal" matter. Clearly, the intuition behind the continuity requirement is a small step in the direction of utilitarian ethics; even the worst-off member of the society might be made to suffer if there is enough benefit to others. The assumption of diminishing marginal utility implies with regard to usual policy alternatives that there are better ways of improving the lot of better-off members than by hurting the worst-off.
But there is one striking case, of great practical importance, where our intuition is in favor of utilitarianism is some form as against any minimax rule. I refer to allocation over time. Typically, we expect future generations to be better off than we are. Should we save for them either directly or in the form of public investments? A maximin rule would surely say no. But if investment is productive, so that, in terms of goods, the next generation gains more than we lose, we usually feel that some investment is worthwhile even though the recipients will be better off than we are.

My own view is that both endogenous and exogenous elements are important in explaining innovation. Incentives certainly play a role, but so does the general state of scientific knowledge, which is not directly produced by profit-making entities.