It's a bug. It has always been a bug, an artifact of the wonkiness of HP in general. There are a number of situations, like falling, like lava, where a character's experience, skill and luck (which is what HPs represent) would have no realistic impact on survivability. For the most part we accept this because HP is so damn convenient.
I think the solution is to have some kind of 'save or die' roll after a given fall distance, with the DC increasing by distance. For example, take 1d6 damage per 10' fall; in addition falls over 40' require a DC 12 save or the character dies from massive trauma. For each 10' beyond 40', the DC increases by 2. (I don't know if these are the right numbers BTW; just an example of the kind of model I think should be used).
That way we don't have ridiculous metagamey situations where people can jump from a mountain because they know they have the HP to survive.