It seems to me very intuitive that a lack of IP protection of some sort discourages innovation.

I cannot imagine wanting to write a book if I didn't have some recourse against people distributing my book freely.

The policy concerns around IP protection for both patent and copyright are clear: the minimum amount of protection that doesn't discourage innovation.

Lawmakers know or should know that we all benefit from a rich public domain, which is why there are limitations on both copyright and patents in terms of both duration and general application, and I am happy to argue that copyright is too strong, particularly in terms of duration (thanks Disney), but I simply can't agree that we "would be better off without any kind of copyright or IP".