Stop signs are made up too. See how far you get driving through all of them without stopping.
Copyright law is already different from country to country.
Much of the heavy lifting is done by treaty-- not so much that anyone is asking legislatures directly to establish and extend copyright, but that it comes part-and-parcel with other international obligations.
Without the weight of such treaties, I wonder how many countries would do without an IP regime at all, especially if they don't see any IP-related export opportunities, so copyright and patent merely limits their ability to make cheaper versions of foreign goods.
I just wanted to say that laws are subject to change.