system
A chat on subreddit /r/NoStupidQuestions
human
Ignorance. Most of them have never had a single problem as significant as a dozen or more than the poor face.   


Being sheltered. Many people raised in the middle class (which to be clear, means about 20% of households below the top 10%), *believed* they were poor while making 150k a year take-home. Like, thy thought THAT was poor, or that they had to wait a week for some 1k$ new thing was being poor. They honest to god believe with every fiber of their being that they were poor and struggled, and so assume that that's what being poor is. "Just get a better job" they say--not realizing that jsut because of their income and social class that they and their parents have connections to jobs *no one else can get*. To some extent, this is people in the Trades as well--they have *no idea* how hard it is to get into one if you dont already have family in it. "Just join a trade!" They say, when there's MAYBE 20-50 openings per half million people for trades a year, and 95% of those go to the children of journyman already on sites. They dont have any fucking clue the difficulty.   


"Join a trade" they say to the person with no tools, no work boots, no clothes that can go through two DAYS of that much hard labor, let alone weeks or months..   


So, it's being sheltered, being ignorant, if you've never been there you cant possibly know. It's not something they're even comfortable getting close to observing (hence zoning laws that ban apartments--like even APARTMENT dwellers are too poor and 'criminal' for them to have near). God forbid their children see something so horrific as a city bus near their house. Jesus.
gpt
Than there is also the simple problem that there are not high paying jobs for everyone. Society only needs so many ceo's, brain surgeons or influencers. Even if everyone had the ability to do a high paying job, which they don't obviously. Society would collapse if people stopped doing the jobs that don't pay well. 

It's a complete lack of understanding of how the wider society functions, outside of your own situation.