Hit points aren't an inherent part of the gameworld. They can model an inherent property of some element within the gameworld. But they don't have to.The ogre has a physical form. Hit points aren't an inherent part of the game world.
Consider hit points - or, rather, concussion hits - in Rolemaster, though. In RM a typical 1st level PC has around 100 hits, and falls unconscious if 20 or so are lost. The toughest human warriors tend to max out at around 250 hits, and fall unconscious if 150 or so are lost. There are abilities - both non-magical frenzies and magical/psychic powers - that can change the unconsciousness threshold.
When playing RM, a creature's hits are a measure of a certain aspect of its physique - its ability to withstand pain, bruising and blood loss. Because this doesn't change depending on who the creature is fighting, its number of hits doesn't change depending on who the creature is fighting.
Now consider 4e. In 4e, a creature's hits aren't a measure of any inherent property (physical or magical) of a creature. They measure a relational property of the creature relative to the PCs - roughly speaking, its likelihood of standing against them in combat. Hence it makes perfect sense to change them depending on how powerful the PCs are.
Different RPGs use superficially similar systems for quite different purposes. For me, part of learning to play and GM a game system is learning what purpose(s) its mechanics are meant to serve. Saying that 4e is ridiculous because it doesn't use mechanics for the same purposes that RM does makes no sense to me. There's nothing ridiculous about designing a game to do thing X rather than thing Y.
The gameworld doesn't have mechanics. The game has mechanics. A gameworld, therefore, doesn't have mechanical consistency. This is a property of a game, not a gameworldIf a Giant (Elite) has 95 h.p. against a 3rd-level party that same Giant has to have 95 h.p. against a 20th-level party, even though those 95 aren't going to last nearly as long.
If a Giant (Minion) has 1 h.p. against a 20th-level party then that same Giant has to have 1 h.p. against a 3rd-level party, whcih is ridiculous, of course.
If a Giant (Elite) has 95 h.p. against a 3rd-level party but that same Giant has but 1 h.p. against a 20th-level party then your game-world's mechanical consistency just went out the window; also ridiculous.
In Rolemaster, the number of concussion hits a creature has tells you something inherent about the creature. Change it, and you change what the description of the creature. If this changes without ingame explanation, the gameworld has become inconsistent.
In 4e, the number of hit points a creature has tells you nothing inherent about the creature. It tells you something about a creature only when you relate it to the level of the PCs with whom the creature is fighting. 4e applies these mechanics very consistently, to yield a consistent gameworld.
In Rolemaster, it wouldn't make sense for a giant to have 95 hits against 3rd lvl PCs but 1 hit against 20th level PCs. In 4e this makes perfect sense. Because the games use superficially similar mechanics for really quite different purposes.
This is utterly system relative. It is true in Rolemaster. It is not true in 4e. I don't think it's true of Gygax's AD&D, either, given that he says expressly that with higher levels hit points (for PCs at least) correlate to the blessings of supernatural forces - and blessings aren't a part of a creature's make up, but rather some external benefit bestowed upon it by an outside force.Hit points are every bit as much a part of a game-world creature's (or PC's) makeup as strength, wisdom, and AC. They're a part of what you are
As Rolemaster (or RQ, or D&D played with hp as meat) shows, it is possible to have a game in which hits points (or something similar) are part of the makeup of a creature. But that is not a mandatory feature of any game using a mechanic of that sort. (In 4e AC does not correlate to any inherent property of a creature either. AC is in part a function of level, and the level of a creature can be adjusted, in conjunction with its status - minion, standard, elite, solo - to correlate with the level of the PCs it is confronting.)
That's not my personal experience. I've found, through play experience, that 4e's system of multiple-statted creature versions is more convenient than Rolemaster's system. The convenience manifests itself both in ease of encounter design, and ease of and pleasure in encounter resolution.Gameplay convenience suggests that off-screen things carry their stats with them at all times as they could become on-screen at a second's notice.