All he could ever do was fall. Falling from planes, falling down stairs, falling out of bed, falling and tripping on concrete, and falling to his knees when it was too hard to go on.
That was his entire life.
So maybe it wasn't Bruce's fault. Maybe he was too weak, too cowardly... Or maybe too afraid to stand up after a particularly rough meeting face to floor. If he stayed down forever, he would never fall again.
But the way Dick put it, it wasn't the falling you should be worried about. It was the landing. And Jason had never learned how to evenly distribute shock or roll out of a landing. So he fell, again and again, but this time he was prepared.
This time he knew how to avoid the pain so he'd have the strength to get back up.