What does Ponyboy remember Cherry telling him? Why do these words come back to him when he is talking to Randy?

When Randy tells Ponyboy that he is tired of fighting and is going to leave town instead of going to the rumble, Ponyboy remembers Cherry saying "Things are rough all over," and finally comes to understand what she meant. It is evident that Ponyboy makes the link between Randy, as more than a Soc, and himself, as more than a Greaser, when he says, "You would have saved those kids if you had been there. You'd have saved them the same as we did."