Without copyright, the value of a book's contents is $0, because the mean cost† for (re)producing it is $0. If a product has no value, you can not create a market for that product. Relatively basic economics.
The ability to create value around a product that has no value of its own requires quite a bit of additional effort. Authors can't hold concerts, after all.
The RIAA's argument in the Napster days is definitely similar, but they were arguing from the point of their production costs not being $0, and copyright is in place, making copying legitimately illegal.
† The cost for the first copy is $30,000 (given a Brandon Sanderson pace), and every subsequent copy costs $0 (give or take a few tiny fractions of a penny).
The ability to create value around a product that has no value of its own requires quite a bit of additional effort. Authors can't hold concerts, after all.
The RIAA's argument in the Napster days is definitely similar, but they were arguing from the point of their production costs not being $0, and copyright is in place, making copying legitimately illegal.
† The cost for the first copy is $30,000 (given a Brandon Sanderson pace), and every subsequent copy costs $0 (give or take a few tiny fractions of a penny).