You have a teenager! Their brains don't work well in the mornings. Just ask them. If they function by noon things are going well. Unless there's something that interests the boy - then he's very good at getting up, right?
But he's old enough to take responsibility for himself even in a semi-awake state. You could change the routine so that he must be clean and dressed before he eats breakfast. Have him set his clock to (gasp!) an earlier time, and call him once, but leave it up to him otherwise. Refuse to prompt or nag. If he misses the bus... what? Does he walk to school? Pay for Mom's Taxi Service? He needs to do what the adults must do when they don't get themselves going.
If your son has a sense of humor, you could give him the National Toe-Staring Award for 2011. :^)