usually its the scalpers who stockpile these "limited editions" because they think they can scalp for it in future or to show some "prestige" of owning atas bottles. these fukers are the ones jacking up the prices and perceived value of whiskies like how they rekted japanese whisky prices. now even cheap shit from japan immediately become expensive shit

but most of the time some folks are more on keeping the bottles that they like to enjoy in future. remember that any aged kind of liquor takes time to create and are based on the tastes of the master distiller years ago

so what makes it special is that the flavor of the past is kept sealed in the bottle even if its just a cheap bottle. most whiskies be it blended or the single malts nowadays are constantly changing based on the environment its aged in, type of wood, weather bla bla so on

for example back in year 2000 you drank a 12yo single malt from Glenfiddich, that was the taste they created in 1988. so if you drink another 12yo now in 2025, the same bottle may not be the same taste as the master distiller prolly has died or changed.

another reason also because over time, some liquors recipe are "tweaked". many liquors like Gordon's gin now due to popularity watered down their gin to 37% instead of 40% to meet rising demands (or fit into country regulations etc).
PS: tho you can argue this is pretentious talk lol, in the end people just guzzle whiskies like water anyway instead of enjoying then theres no need to stockpile 
rule of thumb for buying whiskies that you think you might want to keep, always buy in twos 

that way you can open one for tasting then the other simpan for dunno when to drink