> By that case all art should be copyrighted since our brain stores a highly compressed version of everything we've seen.

Good thing this is already the case! https://en.wikipedia.org/wiki/Berne_Convention

> The Berne Convention formally mandated several aspects of modern copyright law; it introduced the concept that a copyright exists the moment a work is "fixed", rather than requiring registration. It also enforces a requirement that countries recognize copyrights held by the citizens of all other parties to the convention.