I have been riding since the late 70s and have hit my share of potholes and have never even bent an axle let alone broken one. Broken BB spindle wow I would like to see that (On someone else's bike) I have never seen that either. I know it is not correct for this list but I ride off road and hit some really really big potholes and nothing ever brakes. I guess I am just lucky. Don't forget to praise the cycling gods they are angry vengeful gods when not appeased, that could be your problem.
Sam DiBartolomeo Riverside, CA