While drinking my first cup of coffee and reading this article, I noticed that OP mis-titled the original title of the article that was copied and pasted. It was not "Why People Are Poor", but, rather "10 Reasons Why Most People Do Not Achieve Financial Success".
The article was more in the nature of discussing the dumb things people do with their money rather than how they wind up being poor or rich. If you took a random group of middle income folks and judged them on how well they followed the author's advice, there would be a marked difference in the financial outcomes. Those that chose poorly would not be in the ER crowd while the others would be (if they chose to). Most would be somewhere in between.
In a forum so devoted to the concept of LBYM I don't think I have to say anything about how being financially successful has more to do with how you handle your money as opposed to it just being all about how much money you have. Everyone's choices and preferences differ and we all have our own version of "the number".
In spite of all that, this thread has been devoted to the title OP gave, why are people poor? A couple of cups of coffee later, I reflected on where I came from and where I am today - and the hows and whys of it all.
I'm not going to replay my internal Four Yorkshiremen or Horatio Alger bit, other than to say "you guys got to live indoors? Wow, you had it made!"
Did I win what Warren Buffet calls “The Great Ovarian Lottery”? The answer depends on how wide you want to spread the possible outcomes. If it means I was born in a democratic republic with a (mostly) capitalist economy with opportunities as opposed to Mogadishu, then yes I hit it big. If you narrow it to mean I was blessed by parents with the economic and social means to provide access to opportunities most others don't, well, all I got was the "Please Play Again" card.
But, if you defined it as I do, that I got some good genes that made me intellectually and physically capable of being successful, and an upbringing that taught me that my success was more a matter of my effort rather than what life handed me, then I hit the lotto and even got the power ball right as well.
Luck? Again, it depends on how far you want to stretch the meaning of that concept. If you're talking about random fate dictating the dice to not make you a loser, yes I have been lucky. There have been many times that my body should have been getting cold out there on the streets and yet I live on while others didn't.
But luck comes in both flavors, good and bad, and there are many times that the outcome has a lot to do with what you do in response to a situation than it does just accepting what fate dealt you. There's a lot of times that luck tried to play for the other team, I was better or faster and I'm the one who gets to keep walking around.
There are people out there that never got a break, but they are rare and form a tiny minority. As there are their opposite number who got all the breaks. But in the Western world the greatest majority of people are handed a mixed bag of good and bad that they have to deal with. None of us can credit all of our success, nor blame all of our failures, on fate, luck, or who are parents were.
And of course we can't all claim sole credit for success in life.