Why would they? If they don't want to hear from you, wish you'd just kind of "go away" and you keep holding on, they don't want to say anything in case you see it as "communication" and encouragement to keep sending them messages.

If they were polite and knew how to say something they might but your friend hasn't done anything "polite" or friendly for a long time now! And how do you tell someone, "Hey, I don't want to hear from you anymore!" that just sounds so ugly? So not saying anything at all, they just hope you'll quit trying to contact them. If they wanted to be friends, they'd respond to you but since they don't respond, I'd give them up and spend my energy making friends with someone "friendly".