[Request] DND falling logic

So is thinking about DND 5e a while back and was curious about something I noticed. When falling the game places a simple limit of 500ft per round with a round being 6 seconds long.

With what little smarts I remember that seems way off it I ignore it for a while and realize a lot of other weight and lifting calculations are stupid too. With the falling speed being the simplest (in my eyes) base numbers to use.

So given a normal human (assuming proper sky diving position) falls at a rate of 500 ft per 6 seconds with acceleration to reach that speed very quickly (unknown acceleration) would the atmospheric density and or gravity be the most likely be the cause.

The most basic understanding I have might explain some of the crazy physics of the game. I’m aware the Devs didn’t put almost any thought into those specifics but I think it’s a good though experiment.