My quest For 9mm ammo continues
At my local Walmart, they did have a little bit. Apparently a ship had just come in and they sold out of a case of Winchester White Box 9mm 100 round packs in less than an hour - and that's with a three box maximum per customer purchase policy.
Luckily for me, there were 6 boxes of 50 rounds each of Federal 9mm remaining and I purchased my maximum of three boxes. That's enough for all of 1 USPSA match, assuming I have no misses (Good luck with that).
There was no .40 nor .22 and only a few boxes of .17HMR, and 3 boxes of .45 Auto remaining, looking all lonely on the very bare shelves, which I didn't buy as I reload for 45 so I might as well let someone else get it who needs it more.
In speaking with the clerk that opened the locked display where the ammo was sitting, she confirmed they do indeed get, and will continue to get ammunition deliveries. She stated it is highly unpredictable as to when they get it and how much they get in each shipment, but they do get it, typically on a weekly basis.
In short, there's no over-arching Walmart conspiracy to stop stocking ammo - they just can't keep it in stock as people are buying it and buying it both early and often.
Supply and Demand isn't a suggestion, but I'd suggest they'd start increasing the supply if practicable as they're leaving money on the table with this shortage.
Yes, I know ammunition manufacturers are at capacity now and it takes time to get new production lines up and running, but this demand increase wasn't exactly unexpected. In addition, the legions of new gun owners likely aren't going to just put up their new firearms into storage and never use them, so the demand for ammunition will likely remain strong (but not this crazy) in the foreseeable future as these new owners get out and practice and have fun with their new firearms in training, competition, structured practice, or simple plinking, hopefully on a regular basis.