Some of these egg companies are absolutely using the bird flu as an excuse to raise prices. Right next to that 18 pack I bought was a shelf full of eggs that cost $9/dozen. No one was buying them. Just a weird situation.
Meanwhile you just go to a Kroger or Walmart down the street, pay nearly the same price, and they always have stock. It was the same thing with toilet paper early in the pandemic; we swing by Costco, utter madhouse, line out the door, everyone has cartfulls of toilet paper. I tell my friend "lets skip this and go try Target" -> Shelves weren't fully stocked, but they had some, no crazy crowds, we're good and the butts are clean.
Costco's prices aren't even that spectacularly great anymore, especially once you factor in the membership, and if you do a little legwork on coupon clipping (which is so easy nowadays with all the apps). E.g. the Kroger near me almost always has meat like 30% off on Fridays because, idk, its nearing the last day they can sell it or something. Stock up for the week then, way cheaper than even Costco.