Just stupid stuff. See: Empire of the East (book 3 I believe) by Saberhagen, where Valkyries resurrect dead soldiers who wear a certain collar - you'd have to read the book. The question I have at that point is if restorative magic is so easy to come by, why isn't all magic easier?
That's not restorative magic, though. The Valkyries are pre-Change flying machines carrying people up to a lake of life - probably the last one in the world - a pre-Change invention which can heal injuries and revive the dead (and also to Draffut). In short, they're both technological inventions and the people of the series are incapable of recreating them because they usually don't understand pre-Change technology at all. Hell, the lake of life is beyond our current technology, even, along with some other things like Elephant, and the Change itself (But you can see some other simpler examples of technology in existence, like binoculars - which people still had never recreated)
The collars were easily countered in the one series of battles they were involved in, by cutting off heads and tossing the collars off the cliff, bridge, etc that the battles were being waged on, preventing the Valkyries from finding anyone to carry off to the lake of life.
The lake of life was also destroyed near the end of that same series of battles.
By the time of the Book of Swords and Book of Lost Swords sequel series(es), mages were wholly inadequate healers, and the only really effective healing capabilities belonged to Draffut (considered a god by most people) due to his extremely long exposure to the Lake of Life, and to the Sword Woundhealer, which also could not be reproduced.
Finally, a lot of games probably don't even intend to depict a high magic setting despite what you see in the gameplay. Think about how the real world would be different if Lara Croft's infinite pistol ammo, immunity to cold, and wound regeneration were common to even 1% of the population? Obviously the game isn't saying people are actually like that, it's just that the game would be less fun if you could run out of ammo, or couldn't see her rude titties under a heavy coat, or had to wait 6 months to continue playing while she healed up from that broken leg. I guarantee if we see Tomb Raider: Restocking At Walmart, they will sell pistol ammo on the shelves and NPCs will be buying it, and Lara still won't need any except maybe in a cutscene. (Yes I realize the latest TR games feature limited ammo. Back in the day there was no melee attack so you had to default to dual pistols which wouldn't run out of ammo). Some FPS games feature a "first aid" mechanic where anyone can revive a teammate, indefinitely, no matter how much blood or organ meat is lost under the hail of gunfire. Others feature regenerating health when you stop getting shot for a little while. The game isn't trying to say that's legit and worthy of philosophical investigation, only that the game would suck more without it.
That's all "we think it's more fun this way" though, and you can go look at other shooter games where you did have ammo, and medkits (which were pretty magical just for gameplay reasons), and if you're ran out of ammo for all your weapons, well, you had better either run away and try to find more*, or try to beat your enemies to death with your
Mighty Foot (You actually start that level without any ammo or guns because you were taken prisoner at the end of the previous one).
I'm assuming you're remember correctly about the first Tomb Raider games; I never played them. Remembering gameplay is easier than remembering the entire plot and all the events of a book, after all. (I just happen to have recently read Empire of the East, prior to starting to re-read the Swords series(es))
Some FPS games include a "first aid" mechanic where you can revive a teammate, but only so many times before they can't be revived again. I'm describing the Left 4 Dead series, of course. Really it all depends on what the game is trying to be.
* This happened a fair bit in Duke 3D LAN multiplayer
In the Dominions series of strategy games, nature mages create food magically every month (they increase supply) in addition to whatever they're already doing, and they can craft magic items that can produce a certain amount of supply (food) each month, forever. Mind you, supply is per-province, so to feed a large army in wastelands you may want a bunch of them, but it's a relatively simple task. There are also races and beings that don't need to eat at all. A sufficiently powerful mage can also, for instance, instantly conjure a castle into existence, expending only magical gems and one month of time. That is much more difficult than just making food, of course, but there is no way to magically destroy someone else's castles/forts.
P.S. entropy is
confusing and reading its wikipedia article makes me wonder if you were even using it correctly, but like I said, it's confusing and gives a bunch of different apparently contradictory definitions, so I can't even tell. SO CONFUSING. So that's why I did not say "entropy" in that previous paragraph anywhere.
P.P.S. It might be interesting to design a system which used thermodynamics-like rules to govern the use of magical energy. Of course maybe it would turn into "it turns out magic works by drawing energy from the sun, and, well, ha ha, sucks to be the Tippyverse with its tremendously high magical energy expenditures..." Hell, create a post-tippyverse where refugees escape to other planets on other solar systems because "Well, the sun was dying!"
(Of course you also have systems like TES, where the "sun" isn't a sun, but a hole in the fabric of reality left by a fleeing god, through which magical energy flows into reality)