For the past five years now, I've been living off of roughly $10k a year, in the middle of a major metropolis (Minneapolis). I suffered in blinding, writhing agony for years, because I could not afford a $300 checkup. There were days when my throat swelled shut, days when I could not stand, and days I could not sit. For want of that checkup, I lost more business than I would have paid in taxes to make that back.
The average American family is not much better off than me. One tragedy from complete destruction. Once financial mistake from destruction. One layoff from destruction. That's the baseline. I went through all three, I learned a bit about how the world works.
A family spending $25k on child care is spending more than most American workers even earn, even though the average laborer earns $100k. The income disparity in America is enormous. To the person who worries about keeping a roof over their head (if they even have one), the one whose worries are instead about their children will seem wealthy to them, even if those earners do not actually hold wealth by the technical definition of it.
Wealth is a different concept than income, though it is related. Someone making $200k per year may or may not be wealthy in any given portion of the world, it largely depends on how free they are from debt traps and other liabilities, and how much of their income depends on their labor versus returns on investments.
A lot of this is simply just knowledge. No one who knows how car dealerships work will finance a car through the dealership, for example, and many of the truly poor are trapped in usurious loan contracts. But knowing where debt traps lie - and how to avoid them - is an important factor in being secure and, consequently, happy with your place in the world.