Um. I'm probably misinterpreting you, but it sounds like you're suggesting that we should force people to buy things they don't want or need in order to make the market healthy?
If you are saying that, I strongly disagree. Both causally (I don't think that will make the market healthy) and normatively (even if it did, I would need a lot of convincing to advocate that).
If you're not, could you clarify?
> for which the demand would not otherwise exist if the same money had been spent on the repair of a broken window.
Or if the money had been spent on any window.
By "there is no need for a window", I meant "nobody cares if there's a window there". In both situations, money transfers from the shopkeeper to the glazier, the glazier does some glazing, and the shopkeeper ends up no better off than before.
There's no need for any voluntary purchase, by definition. You're arguing that we should only spend so as to maximize utility, but utility is subjective and that's why we value markets over individuals. After all, what is the utility of the foregone book? It may merely afford pleasure to the reader, or be hurled across the room. It doesn't matter; the book's significance lies not in its content but in the fact of its production, for which the demand would not otherwise exist if the same money had been spent on the repair of a broken window.