The nature of the video game medium all but requires for players to develop behaviors that would simply not make sense in universe. Zelda players roll everywhere, FPS enthusiasts reload after firing a single round, Atlus fans cringe whenever they see a matador, and so on. They're little inconsistencies that simply make the experience easier on the player, even if they threaten immersion. And Runescape is, at its heart, not particularly consistent or immersive, so many players have an arsenal of little tricks that, if attempted in a living, breathing world, would be met with confusion at best and terror at worst.
Sometimes the littlest behaviors make the biggest difference. You and I know that having a duplicate of a certain item makes it easier to find in your bank. NPCs undoubtedly wonder why we're demanding duplicates of their priceless, unique heirlooms. They may also wonder why we're so content with dumping items worth the price of a small house on the floor to make room for them, but that's neither here nor there. Time is money, after all, and time spent looking for that one useless item is time that could have instead been spent punching a god-tier abomination in its squishy bits, for the chance at making more money than even the King of Varrock can imagine. Let's be honest here: does someone with that kind of power really need a second vial of slime?
The answer is yes. Yes they do.
Of course, sometimes that god-punching pays off in a different way. Clue scrolls tend to be fairly divisive, with some players arguing that they're a fun but ultimately unrewarding diversion, while others claim that they're an unrewarding diversion. The important question is 'who put them there?' I can't help but imagine someone burying a set of clues near a cache of otherwise valuable loot, then hiding the first in the gullet of some horrifying beast that is probably in the process of transforming the human body into its base nutrients, and I just have to ask how many clues survive the process. More importantly, what happens to the clues that aren't found or solved? Who would even do something like that? Does some poor farmer accidentally uncover a third age coat while planting his crops, all because an adventurer didn't bother to take a charred and bloodied slip of paper from some demon? And, perhaps more importantly, does that farmer buy half the known world after doing so?
Of course, that kind of wealth takes us straight to the darker side of the game. The most valuable items in the world are tiny wax paper crowns. They're the sort of thing that anyone can make as long as they own some scissors, a bit of tape, and a marker. It shouldn't be difficult to find any of those things, and I'm fairly certain the shopkeepers in Ardougne could crash the banks of all of the world's richest adventurers for a couple hundred coins. Assuming players don't crash it themselves through alchemy or glitches - gold would most likely not have any value if the population at large knew how easily you could pull it out of thin air. Perhaps rune essence would make for a better currency: the supply is unlimited but access is not.
The lesson here is that the world and its economy look a bit more fragile than slips of paper that have been fermenting in the gullet of a giant worm, but looks are apparently deceiving. Or perhaps these are the dung ages, and the peasantry is just that uneducated. Either way, there is plenty of profit to be made, and you've wasted enough time reading this article. Go kill something for money to make up for it. Drinks are on you.