Meta: I'm personally marveling at how such a laughably simple thing ("www." or no prefix) can become such an unnecessarily complicated technical debate due to archaic infrastructure.

As an outsider (non-web software developer), I have to say debates like these hint strongly (IMO) of a cargo cult technology culture surrounding web development. Of course I get that we have to work with existing infrastructure; however I must admit it's surprising so many people seem blind to the idea that maybe the issue shouldn't exist in the first place.