Because they think they deserve it. "Oh, he deserves to be poor, its their fault". This along with the hope of poor people to get rich, constitute the fundamental pillar to keep the capitalism scam going.
exactly,
even though most people are worse of n capitalism (by design), many of them support it, in the hopes of ever becoming the top of the food chain (no matter how unlikely), and the ones that do not support it because they are so far down the chain they can't ever hope to be even somewhere near the middle, they are too poor to matter anyway.
Also, a lot of propaganda against anything that undermines capitalism.