Actually, no rules in D&D tell you how far you fell. No matter what, you hit the bottom at the end of the round according to the rules. You can fall ten feet or ten thousand feet and you will take exactly the same amount of time to hit the bottom, and you will ALWAYS hit the bottom before 6 seconds.
Now, I agree, this is utterly ridiculous. But, that is what the rules say.
It is hard to accept because the definition you are using and the one
@AlViking insists that simulationist rules are diegetic. Which means that they actually correlate to what is happening in the game world. For rules to be diegetic, they MUST tell you anything (even the tiniest bit of information would be enough) about how the result occured. That's what diegetic means. I'm simply insisting that you use the definitions that you yourself agreed to.
By your definition ALL mechanics are simulationist. Because all mechanics tell you the result of something and don't tell you how it happened. Rolling dice in Monopoly are simulationist according to you. No matter what, all mechanics are simulationist if simulationist mechanics don't have to actually describe anything other than the result because all mechanics, no matter what, do the same thing - describe a result. The cook popping in after a failed lockpick check is 100% simulationist by your definition. Since there is no need for any causal chain between the mechanics and the result - after all the mechanics in no way describe HOW the result was achieved, thus, there is no need for any causal link between the mechanics and the result - then any result, no matter how farcical - like falling at light speed, but only taking limited damage - is 100% simulationist.