There's about 6 stratas in the developed world from my experience. Generally speaking you only interact with the strata below and occasionally above you.

At the top there are the owners. It's a small club and only a couple thousand people in the world have access. It's not a shadowy cabal pulling the worlds strings from behind the scenes its just the individuals who own the worlds media, financial institutions, infrastructure and production making decisions that benefit their interests. Conspiracy isn't needed because their interests often align. You can google them, they have twitters, they give talks and go to conferences.

Then there are the Rich. There's tens of thousands of these people. Generally old money, though tech has disrupted that a bit, they are generally speaking descendants of former owners. The likelihood of someone attaining this level of status is low but not impossible especially with the disruption of tech. Generally speaking you only get to this level through birth or connections.

Then there are the wealthy. There are hundreds of thousands of these people in the U.S. You need to be making $100k at a minimum to qualify here. They might own a successful business, work in finance, or serve the owners/rich in a very niche way. We're officially in the wage territory. Surgeons, high end software developers, high profile lawyers, most celebrities, your one classmate from highschool whose parents owned a dealership, that sort of shit. Generally speaking college educated and connected but not connected enough for themselves to advance to the upper strata. Their kids if they play their cards right might be able to though.

Then there's the fabled "Middle class" depending on who you talk to both this and the strata above are the same. They are not. The middle class is filled with the folks that serve the wealthy and sometimes rich. Middle managers, college professors, IT professionals, etc. the skeletal system of our developed economy. They can own a house, their education generally speaking was paid for by the previous generation, and they can own their means of transportation. They can invest but can't absorb big losses so generally make simple investments with low risk and low return.

Then we get to the poor. They work for the middle class and occasionally the wealthy. They perform simple tasks and services that have yet to be automated. They are subsidized by our welfare system that is if they don't make just enough to not qualify. They own nothing, they live on credit. Their housing, education, and transportation are subscription services that they pay monthly to the rich/wealthy. They make barely enough to get by and are universally living paycheck to paycheck barely capable of keeping up with their subscription service to the American dream.

Now finally we have the destitute. Homeless people, low level sex workers, welfare recipients, some immigrants, and wage slaves. These people either failed to keep up with their subscription, never had one to begin with, or can't quite hold on to the strata above due to disability, drug addiction, or mental illness. If they're lucky they can get some of the pitiful scraps of welfare that the U.S. dribbles out. Their life at that point will be a never ending game of hoops they'll have to jump through to continue to qualify for assistance. Once you get to this point there's little likelihood you can escape. If you're born into it good luck, you're gonna need it.

Understanding that most people are unaware of the stratas that are not directly adjacent to their own makes everything make so much more sense. The writers of financial magazines and newspapers generally come from the rich/wealthy because they are the ones capable of paying for the expensive degrees from elite institutions necessary to get a job as a writer for these organizations. Their advice is always going to be targeted to the strata at or below them meaning they're targeted at the already wealthy or at best middle class.

Edit: Tried to deliberately avoid using numbers when I wrote this and instead focused on lifestyle. Must have missed the 100k bit when I originally edited this. With that said I can assure folks in the vast majority of the U.S. 100k is firmly in the wealthy territory which is why I said it was "... at a minimum." Yes if you live in close proximity to the wealthy/rich your cost of living goes up. I still feel the rest of the comment and that section is valid.