Remember that things in motion continue in motion in motion unless acted on by an outside force. This is one of Newton's laws. What this means is that except for friction, it takes zero energy to move on a level plane. This is Loebner's First Argument for the existence of God. I am an atheist, but if I were a believer, I would say that this fact is a gift from God.
Ball bearings have a very low coefficient of friction.
If ball bearings had been invented before the steam engine, we would be living in a very different world. However, it was not pens, but guns which stood up to Hitler and the Nazis in WWII, and it was the guns of the Union army that freed the slaves in the the South. I was sexually abused as a child. I was a virgin until I was 22. The abuse was sexual deprivation.