not the point. Not even a little. Let it be a mile up if you like.
The point is: Sometime ago someone decided to make it 20d6. It was said thus it was core. Why 20? maximum damage of 120 to minimum damage of 20 -some for circumstance, Expected dmg is 70. 120 is something a lvl 12 warrior has and he will most likely make the dc 15 save with ease.
Do the 20d6 have some meaning? Are they ballanced to something? was it to make the bullrush less powerfull? was it just random? Are there no ancient scriptures that tell the tale of why the gods decided that a lvl 15 Human Warrior basically CANT die from hitting the ground at terminal velocity? Especially since safety measures are so cheap at hand.
All of the following might be an "origin myth" concerning D&D, but if it is a myth it is a myth that existed AT the time of the origin of D&D. In other words, I started playing the original D&D when it first came out and this is what was commonly understood to have happened after AD&D 1st edition came out. I can't remember where the story was first disseminated, but I think it was in an early Dragon Magazine.
The story goes like this: Gary Gygax needed to quickly write a rule about falling damage for the Players Handbook (1st ed.). He typed up that falling damage would do "1d6 per 10 feet per 10 feet fallen". No example provided, just that rule. It also set the maximum at 20d6 which was a nice round number to remember, but the MAXIMUM dice would be adjusted up or down by the surface landed on. ABOVE ALL, the rule said the DM would assign what happens to you, but he would probably just use the d6 dmg in order to give the PC some chance of survival despite not being "realistic". Off went the rule to whoever was editing the book (Mike Carr perhaps? Editing the 1st Ed. Players Handbook that came out in 1978?).
The editor got hold of it and thought the second "per 10 feet" was a typo. It wasn't. It was just a complicated way of saying you take 1d6 for falling 10', 3d6 for falling 20', 6d6 for falling 30', 10d6 for falling 40' etc. (1d6 for first 10 feet, 2d6 for the second 10 feet you fall, 3d6 for the third 10 feet you fall, 4d6 for the fourth 10 feet you fall etc.). Believing it a typo, the "extra" per 10 feet is chopped off.
That left us with an original 1st ed. D&D having the rule, 1d6 per 10' fallen, maximum of 20d6 (the adjusted up and down part was harder to remember.)
Been that way ever since.
Remember, this rule was thrown together by minimal staff/resources and during a time when the rules had things in them like "the DM will determine what happens using common sense."
cheers,
L