In single-player games, are there any tricks that developers use to deliberately extend players' gaming time?

As mentioned above about increasing difficulty, the same producer can reduce the drop rate of certain necessary items, forcing players to grind to extend the game time. Nowadays, the drop rate of games generally uses "pseudo-random", which means that with a drop rate of 10, if you don't get a drop for the first 9 times, it will definitely drop for the tenth time. This mechanism ensures that "bad faces" players will Gameplay.