There's relative poverty in the US still. Currency still has relative purchasing power. Saying a person living below the US poverty line should be put in the same class (upper class) as Jeff Bezos seems disingenuous as best.
Comparing the poor of a rich nation to everyone else is an apples to oranges comparison. The poop still struggle hard in the US.
If you are poor to the point of relying on public assistance to meet basic needs, an extra $60 up front even if it will pay off over a year means foregoing other essential expenses now.
But the bigger cost in many parts of the country is the space needed for inventory to maximize the benefit of bulk purchasing. Sure it works well for my family, but we live in a decent sized suburban home with an second refrigerator, and a storage closet converted for additional pantry space.
You can also tag along with someone else that has a membership if they’re willing to offer you their time.
Costco serves the upper class.