I get all that, but that doesn't balance out the issue of how abstract HP are gained. I'll give you an example of how luck/favor works out.
When I was in 7th grade I was hit, full on, by a car when I was skateboarding.
Yes, but... you were a commoner, without any class levels. You might, at best, be hit-point equivalent to a 1st-level wizard, but not even a 1st level fighter. The game is not really intended to worry too much about 7th grade you. It is worried about much more adventurous sorts - people who can leap off 4 story buildings, and walk away.
There are very few real-world examples that are anything like 7th-level Conan in a fight. 7th level Conan would see the car coming, and stop-kick it, and walk away. He took the same number of points of damage as you in the hit, but his capacity is literally fantastic.
You can bring up the "game balance" argument, but there are other ways the game is balanced out, so I really can't buy that anymore.
There are other ways a game can be balanced, sure. And in 5e, this is used slightly less - with wizard-types using d6s. And, yes, if you built a game from the ground up, you could, in theory, even things up across the board. But 5e is not that game.
Most games are not that game, either. Most games have at least the option for a character to use part of their overall build resources to enhance their damage capability. In D&D, you do it via a class package. In Gumshoe games, Health is bought the same way every other skill is - so if you have lots of health, you are less of a general skill monkey, and you can't have as much spellcasting (or whatever high weirdness the system allows). Fate games have skills and stunts you can buy to enhance your damage capacity - and as a balance if you buy them, you can't have other things.
Broadly speaking, in role playing games, the ability to absorb damage is no less an important capability than the ability to dish it out in any particular mode. You should then expect that some character types will want more of it, other less of it.