Contrary to popular belief, copyright law doesn't exist to ascertain dominion from an author onto it's creation. It exists to regulate exchanges and distribution of such creation, giving a controlled and finite monopoly to the original author with a guarantee that said creation ends up in the public domain. GPL exists to bypass such monopoly and implement a form of public domain (copyleft) that is compatible with copyright law.

but it is a large enough problem.

Wasting man years is precisely the problem. Our collective knowledge is boundless, but time is finite. See the problem here? Why would we want to waste the effort of future generations with the problems of yesterday?

So that an individual can live more comfortably with exclusive privileges to something that benefits all of mankind? We shouldn't be working towards selfishness and arbitrary contractual law.

Agreed, there are much better reasons for doing so.