I know guys who shoot 10k+ 9mm rounds a year and don't reload. They stockpile at least 25k for personal use. It's easy to shoot more than 10k 22lr in a year.
Stockpiling to save money is a very valid reason. Even comparing to prices 2ish years ago there are some pretty crazy price increases.
Wildcats used to be $17/500, now they're almost $30.
Rem/Fed/CCI used to be $25/500, now they're almost $50.
The weak Canadian dollar is of course largely to blame but our dollar dropping 20% compared to the US doesn't account for an almost 50% increase in price.
If the tend continues a brick of 500rnds of bulk ammo will cost $75-100 in a few years.
You do kind of need to differentiate between hoarding and building a hoard. There are guys with hundreds of pounds of powder during a powder shortage but they've had their hoard for decades now; they have nothing to do with the current shortages.
Building a stockpile during a shortage does of course worsen the conditions and extend the duration of the shortage. Don't forget that those who stockpile now are essentially removing themselves from the market for a while. A shortage can easily be caused by everyone buying one brick more than normal for a given period of time. Those who buy tens of thousands of rounds in one shot are more visible and individually have more effect but overall aren't that common. Most of my friends who normally keep an inventory of 0-1 bricks of 22lr now keep 1-3 bricks each. Even my dad who was a buy-what-you-need-on-the-way-to-the-range kind of guy now keeps a spare brick in case there isn't any available. All these mini stockpiles add up far more than the relatively few people who buy 25k rounds in one go.
At the start of the panic buying in the US (post Sandy Hook shooting) I had maybe 1000rnds of 22lr in my personal inventory. I've bought little bits here and there and I'm now sitting on near 20k rounds after two years without dropping thousands at a time or buying out entire stores inventory. If you do the leg work and research it isn't that hard to collect a little at a time. 20k rounds/2 years means I'm buying less than 2 bricks/month more than I'm shooting. That's less than 200rnds/week. Is that unreasonable?
The system I was using was every time I was in a store that sold ammo, I'd check if they had any. If there were any bricks (even one), I would buy one. I would only buy more than one if it was a very good price. It only added $30 or so to the bill each time which isn't that hard to afford. With the amount of automotive/motorcycle/wood working/outdoors stuff I do for hobbies I find myself in a Walmart, Canadian Tire, LeBarons, SAIL, or other stores that sell ammo at least once every week or two. Over time it built up. Over half the times I checked there was no 22lr ammo at all. If I had needed ammo at that very moment I'd be quite annoyed. Now that I have a comfortable stockpile I only buy 22lr ammo when it's a decent price or something special. If someone is very short on 22lr ammo there was a large order that came in at Hirsch Precision of SK and Lapua ammo. It's ultra premium stuff at relative prices but it's available. A good chunk of my stockpile is Eley, RWS, SK, and Norma as I do a good deal of precision 22lr shooting. If I spent all the money I did on 22lr on the cheap stuff I'd probably have over 50k rounds.