> People you might consider to be living in abject poverty might not be so downtrodden as you suspect

This is true, until they have a medical emergency that breaks them because they can't afford it, or the furnace in their house breaks, or they are reno-evicted by their landlord, or their car breaks down or whatever

You're broadly right that money doesn't exactly buy happiness, but it does prevent or mitigate a lot of unhappiness