Games

There are ways to make inventory management fun, and there are ways to make inventory optimization that actually matters. But I guess you could call it a puzzle, a very light puzzle, in the same way you'd have to think how to pack stuff for staying two weeks in a single medium-sized luggage. And I don't see how that detracts from the gameplay at all. Having to solve problems in a game is hugely interesting to me (and to many many people).

Usually the point of having limited storage is to convey the intention of the game designers that you shouldn't be hoarding every item you come across. In the same way, if you have unlimited storage, it tells you that you should be picking up everything. Conceptually, I'm fine with both, but making the player make choices that matter is way more interesting to me, and makes for a better game most of the time. For example, Extraction games are a clear case of how inventory systems can actually become a core part of gameplay, and it's obvious that those games would be less interesting if you just had infinite storage. ARPGs are also a big example of this, it's made so that you have to pick and choose loot before coming back town, and the game wants you to come back town, it's an important part of the gameplay loop. Outward has one of the coolest inventory systems I've ever seen, and it's super simple, just by having your stuff inside an actual backpack on your back, that affects combat, and can even be damaged, and you have this nice assortment of different bags to choose from, with different looks and traits. CRPGs have limited/realistic inventory systems where you have to spread loot among your party members before having to go back to civilization. Survival/Survival Horror games are heavily dependent on the fact that the player has limited inventory to create scarcity and make the player make choices.

Again, casual inventory mechanics have their places, but saying it should be in every RPG/Game is just wrong. Can you imagine a dark/low fantasy RPG where you can just have unlimited health potions in your backpack? The premise is instantly ruined.