People are clearly willing to write and publish a book even with no payoff. If you had taxes and subsidies, even more authors would write to the point that most authors can't live off of writing, since clearly they are willing to write enough to flood the supply of books until most authors can't make it.
The whole point of subsidizing was that authors can make a living, perhaps. I am not sure I follow you. But also, if subsidies are a thing, wouldn't you agree that it is better spent on issues like these, however?