Glaucon becoming dialectic

Towards the end of Book VII Glaucon and Socrates discuss becoming dialectic. At 533 a, Socrates tells Glaucon, "You will no longer be able to follow, my dear Glaucon." I think the reason Socrates tells that to Glaucon is because Glaucon isn't far enough on his journey on the divided line. Because dialectic is at the end of one's journey of learning, one cannot be told what it is. Just as Meno wanted Socrates to tell him what virtue is, Glaucon is doing the same thing with the issue of dialectic. And just as Socrates didn't expressly tell Meno what virtue is; he is doing the same thing with Glaucon and dialectic. It is just foolish for Glaucon to think that Socrates will tell him all about becoming dialectic because even Socrates admits that he hasn't accomplished that yet. And that is the beauty of it all; we are in the same way just like Socrates in that we don't know it all, however we are able to use the teachings of Socrates and others to help us on our way to becoming dialectic.