I was trying to speak against the very error you seem to be making, i. e. the idea that IP rights have either only good or only bad effects. They're always trying to strike a balance between conflicting goals.

Would any books be written without copyright? Yes, of course – although the laws go back to the 17th century, so it's hard to argue that there ever was a golden time of freedom, considering the printing press was newish at the time and the collective creative output has, even per-capita or GDP-adjusted, increased by about a dozen orders of magnitude.

The two mechanisms which I consider "basically sound" is that (a) financial incentives generally work to stimulate creative output. It's not the only motive driving the useful arts, but you'll have a really hard time showing that it's a net-negative, considering that limitless evidence for the efficacy of financial incentives.

The other mechanism is (b) that the restrictions on distribution created by IP laws diminish the actual usefulness of creative output, which includes the number of people having access to it as one factor.

Both mechanisms are obvious, yet they work in opposite directions. The total benefit of IP is (simplified) <works created, i. e (a)> * <people reached, i. e. (b)>.

There are some examples for how to avoid this conundrum, such as 'fair use', or the government (or interested groups/individuals) buying IP rights and donating to the public domain. I also believe quite firmly that copyright terms of death+70 years are far beyond the point where they create enough benefits in (a) to offset the losses in (b). The situation for patents is a bit more murky.