Isn’t that confusing the theoretical cost of production with the real cost? In real terms, yeh, you would divide by 7 billion if you were providing a copy to everyone alive on the planet but, ignoring real demand, you could theoretically keep producing copies for the rest of eternity without further adding to the cost of manufacture.
Obviously, you’d have to come up with some way to counter the eventual heat death of the universe, but provided you did that there is theoretically no upper limit to the number of copies you could produce once you had overcome the initial production cost.
A book is perhaps a bad example; in an online shooter, once the cost of design, manufacture and hosting has been accounted for, it makes no difference to the developer how many bullets each player fires. The cost of the information representing the bullets is 0, given that there is no upper limit to the number that can be used as there is no extra production cost to firing more of them once the code has been created. The game itself has a finite limit to the number of consumers and therefore holds value, but the production cost of the bullets fired within the game is 0 because they are essentially “pure” information.
