I think by now we have all noticed Riot's tendency to retire certain skins, making them unavailable for purchase. In some cases, it makes sense: frequently the skins they retire are really old and are no longer consistent with the graphical quality of the rest of the game.
But let's actually take a look at that statement and analyze it for a moment. When has that stopped them before? Look at Taric, Sion, and Sivir. I think many people would agree that these champs (and several others) are not exactly "consistent with the graphical quality of the rest of the game", but you won't see Riot "retiring" these champs. No, instead they do visual updates (albeit at a very, very slow pace: people have been waiting on updates for the three champions previously mentioned for a long time).
But some legacy skins aren't even outdated when they are retired. Look at Evelynn's Masquerade skin, or Zilean's Time Machine skin (in my opinion, the two best skins they possess), both of which have been retired to the vault, while fairly boring and unimpressive skins remain for both champs (I'm sure there are dozens of other examples of this, I'm just using the two that jump to mind).
I'm not even talking about the limited edition skins, like the seasonal skins, those make sense to me. They were clearly designed to be halloween or christmas skins, or whatever, and making them available for a short time makes sense to me (though I still think making them available again would probably boost their sales, and I feel bad for the poor artists and designers who worked so hard on them)
What I am wondering simple: why? Why does Riot do this? The only possible explanation is economic: they are creating false scarcity, making these skins collector's items, so that the very, very, very few times they actually open the vault and allow people to purchase legacy skins, they will get more sales.
And yet, that argument still baffles me. Is the influx of sales during the absurdly rare openings of the vault really enough to compensate for the sales lost by making your merchandise unavailable at all other times? Imagine if some other business tried this model. Imagine if a car dealership made one particular model of car unavailable at all times except a certain week of the year, one which they don't announce ahead of time. Do you really think that would boost the sales of the car in question higher than if they just sold the damn thing like every other car?
Am I missing something here? This is not a rhetorical question, I am honestly lost. Why does Riot retire these kind of skins? How does it benefit them? What exactly am I not seeing, what do they know that I don't? The people who run Riot are very smart folks, I'm sure, so I know they must have their reasons, but for the life of me, I can't understand it.