Earlier quoted context omitted.
And this is exactly why I only shop at Costco. While other retailers try to get me to buy more stuffs, Costco try to make sure I'm satisfied enough that I'll renew my yearly membership (their main profit source). The incentive structure aligns very well.
Buying in bulk is about having the ability to both afford next week’s food this week and have the means to store it. Not to mention the annual subscription. Responding to a comment about dollar stores preying on the poor with, “that’s why I shop at Costco” is… a choice.
At minimum that's everyone on a normal paycheck, paid every two weeks. There are situations where someone couldn't get together a few days' pay at once, but that's a tiny fraction of situations.
And the means to store most food is a two foot square of space in a room somewhere. And then most of the rest fits in the empty fridge space you already have.
And there are deals there that can be useful for your wallet right away. This isn't something where you have to put up a ton of money for months before you benefit.
The biggest issue is probably that costco isn't easy to get to.