As I stated in an earlier post of mine (and I'm assuming Mobius is using Paradise Lost in the same sense that I am) Paradise Lost is metonymy for literature in general. Fine. Don't read Paradise Lost; but if you want to be considered educated you have to have read SOMETHING. Paradise Lost was initially just an example of a work of literature.
As you and I have both pointed out, this raises the question of what is to be expected of an educated individual? The academic community has unofficially adopted some sort of standard for an education, however. References to older Literature abound in modern literature and even cartoons and comics. If you're educated, you get the allusion and the point is made. If you don't get the allusion, the author probably isn't talking to you. You can claim that an education is what you make it out to be, but the reality is that being able to have an academic discussion entails a certain amount of conformity. If we're talking about politics, and I describe someone as Machiavellian, you either get it or you don't. If you've read The Prince (or at least have a working knowledge of the principles) you understand the point I'm trying to make.