Look: public infrastructure spending stimulates the economy on multiple levels; directly, through spending on contractors and suppliers (who in turn buy from their contractors and their suppliers) and indirectly by creating public benefits that create new opportunities and enable new industries; and through the fact that it engenders stability (a dam has a lifespan measured in centuries if it's maintained, a functional transportation link is not likely to vanish overnight, and so forth). The thing is that these benefits are diffuse enough (though they are measurable) that no single commercial entity can afford the risk that they might not be able to capture those benefits.

The blinkered view that all public spending is automatically evil prevents clear discussion of the possible alternatives. Not all public spending is equal, some projects deliver more overall benefit than others.

I guess my take is that those who are strident in their distaste for any public spending are patsies in the hands of the special interests who are trying to capture as much of the benefits of public spending as possible.