This is interesting, because back when I was still playing one of the frequent topics of discussion[1] on the RS3 side was the rampant in-game inflation. It's interesting to see an alternate explanation for it.
The Runescape economy is pretty interesting in general, in part because the community maintains such an extensive price history of every item, including commodity price indexes[2]. The wiki even has a page that gives a basic economics lesson[3], including supply/demand curves, arbitrage, and price controls. (And there's also the constant accusations of discontinued rare prices being artificially inflated through insider wash trading)
[1] https://old.reddit.com/r/runescape/comments/maohi7/the_cause...
[2] https://runescape.wiki/w/RuneScape:Grand_Exchange_Market_Wat...