mqstout: Post 2, probably going to be merged:
This is also an issue in ttRPGs with loot, like traditional D&D. The party will hoard spells and potions. The main reason being they're usually of lesser effect relative to their costs. The games are about the action-economy in combat, and reading a scroll that does half as much damage as if you directly cast the spell is basically useless, especially when you consider the cost of it. (Now non-combat consumables: topping-off healing, divination, very situational spells? They're used quite well and a lot.)
The issue of consumables being overpriced comes up in the Wizardry series. In Wizardry 8, for instance, scrolls are both expensive and unreliable (they check against your Artifacts skill and can fizzle or backfire, wasting both the scroll and the turn); when you also consider the fact that many of the scrolls aren't that powerful, they end up feeling pointless. There's a similar issue with potions, to the point where the best use of the stronger potions is to sell them, and the best use of the weaker potions is to mix them (requires Alchemy, which doubles as one of the spellbook skills) is to sell them. (Note that you can't learn spells from scrolls in Wizardry 8; you need spellbooks for that; in this way, the game feels more like how D&D should work than the actual licensed D&D games handle this.)
In Final Fantasy 5, Shurikens are far more expensive than they should be; it is more cost effective to throw money at the enemies instead of using it to buy shurikens! On the other hand, this is the game with rods that can be broken to cast high level attack spells early, ninja scrolls can be thrown to deal a lot of damage cheaply, and chemists can learn to mix consumables for a variety of powerful effects (including a full revive well before you get the Arise spell, and an HP drain that's as strong as the Bahamut summon).
One other issue that affects games is when they make it a pain to use consumables. Final Fantasy 2 (pre-GBA) does this; each character has 2 slots that can be used to equip either extra weapons or shields (you can switch during battle without using up a turn) or single-use consumables. Even worse, all single target consumables are self-only during battle, which is a problem when the item is a Gold Needle or Phoenix Down (both would cure statuses that prevent them from being used in the first place).
Later versions of FF2 (GBA and later) can be quite fun with consumables, except for the fact that they don't exercise any of your stats or skills. In the speedrun (GBA or PSP), the strategy is to buy a lot of Fire tomes, and later Teleport tomes, and just use those to win battles you can't come from. Being able to carry 99 of them helps, as does the fact that you no longer need to equip them in advance.
mqstout: Besides the comment on Fell Seal that dtgreene already made (I'm glad I convinced her to play it!)... The other reason is so many games never give you reason to use your consumables!
J Lo: Baldur's Gate is sort of like this. If you are playing a warrior class, you will probably invest in high strength. The game is
very generous with strength potions. Some of them set your strength to 18, but if your strength score is already 18 or higher it's pretty much useless.
That is, unless you're in a situation where you actually want to lower your Strength. (Do the potions work that way?) Such a use casee is rather unusual, but this could be useful if you need to do controlled damage or intentionally over-encumber a character.
(Speaking of controlled damage, in FF5 there's a Mix that does 666 damage if it hits, and in the GBA version (and later) you can eventually use a couple items to do 1000, 2000, or 3000 (you get to pick) damage to all enemies.)