People don’t seem to appreciate a key tipping point in the supply and demand curve. So long as a stable product is available on demand, demand itself tends to remain low relatively. The moment the demand for that product exceeds supply, demand tends to spike. This is most dramatically seen in gas shortages: nobody worries about getting gas, then just fills up whenever they need it, but the moment there’s any hint of gas being not available, everybody races out and buys up as much as they can topping off whatever containers they can. Likewise, ammunition supply behaves the same. People do not buy all that much ammo a time usually, but when there’s any hint of a shortage everybody wants to buy up as much ammunition as they can - so the demand triples quadruples or more overnight. The supply-chain empties out and suddenly we have a real shortage just because there was a very slight shortage briefly. Of course done this inspires lots of conspiracy theorists to claim all kinds of absurd schemes going on by evildoers in the background.
Preppers!
Of course, you can’t store something like gasoline for very long, so buying a whole bunch extra wouldn’t do much good. Ammunition will last a very very long time when stored properly, and probably won’t be getting cheaper anytime soon.
ctdonath2 nailed it.
People don’t want to ever face a shortage of ammo again, so everyone’s goal is to lay in a lifetime supply of ammo as quickly as they can. With the prices of .22LR, this is actually achieveable from a cost standpoint. 20k rnds of .22lr at .06/rnd is only $1200. So, everyone has allocated money in their personal budgets to buy .22lr to stockpile - hence demand outstrips supply and will continue to outstrip supply for the foreseeable future.