I don't think that's the real answer. Each of your bullet points has some truth to it, but is far from the whole story:
> you only need to borrow if you don't have money.
> you can only save if you have money.
Certainly more income makes these easier. But consider the following impossible-to-conduct-in-reality-experiment:
Set group A to be a set of 100 randomly selected poor folks who are only qualified to be cashiers or stock shelves. As group B, select a random set of people who currently earn 6-figure salaries and doom them to only ever work the same class of jobs as group A for the rest of their lives. I would not be surprised to find that the formerly wealthy would, in general, borrow less and save more.
> healthy food costs more than unhealthy food.
While an optimal diet does certainly cost more than a calorically-equivalent amount of cheetos, you can shop at walmart - buying only eggs, oatmeal, and bananas - with the probable result that your diet will be both healthier and cheaper than those of most low-income families.
> good attire costs money.
Maybe so, but anyone can get a dress shirt/jacket/slacks at a thrift store for probably less than $30 all told. It won't be high-end clothing, but will at least look professional.
> based on whether they sound like something a poor person would write.
Idk about this one. What would a poor person write? Is this just a matter of whether they have good grammar? Nobody (almost nobody?) is conspiring to keep the poor stuck where they are. I don't think anyone would reject a qualified applicant just because they have no money.
I have no hard data to back this up, but I suspect that most of the chronically poor's lack of success, and their poor decision making has much more to do with the fact that their upbringing has not instilled into them (at least not deeply enough) the idea that their current behavior can affect their future wellbeing.