Unfortunately, no one likes a short game. But the problem is... even the biggest games (both the in-game world itself and the coding needed), such as a RPG game, often still comes out to a short amount time needed to win the game (a short game). How many of you RPG players, beaten those massive epic RPGs in 3 days? So, even with such a massive RPG, the game time playing it is still very short, and it already took a massive amount of coding too.
The amount of work required to add even minutes onto game play time, is unfathomable, and really the only way to "cheat" it is to not do it via game play but via having them watch cinematics, laughs.
The only games to really reach long (over 3 days of typical old-school RPGs, and excluding speed~expert runs) game plays (not cinema based) would be (in my limited knowledge) the TES (Skyrim) games, and those are the most massive RPGs of RPGs... the amount of work needed for that.... yeesh.
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though to state the obvious, repeating what XanMag said already, quantity doesn't mean anything if it's not quality-quantity, hehe
(most quest games are made by noobies with just a lot of Objects and clicking~Verbs, 'hide and seek' games, with whatever degree of puzzles, and not even hardly any descriptions either, so, this isn't very immersive, nor enjoyable)
quantity is the worst
quality is decent
quality-quantity is the best