.01% of the population own like 90% of the wealth, or some shit. No ones saying they should be making 70k a year. They make the shit I use, make some money. But they shouldn't make so much, the money that is left over isn't even enough to pay for some coommoners roof, food and shit. They make TOO much now. It needs to come down some, so the workers wages can go up and afford a roof without having to work 2-3 jobs and then proceeding to die at 30 from stress, cause even with 2-3 jobs they still barely make it. Folks makes less money each year cause of inflation. Unless your contract has a mandatory yearly raise equal the rate of inflation,which most don't, your salary becomes more and more valueless. Inflations gotten to the point, with wages staying the same, folks can hardly afford basic neccesities. And its rather difficult to go to school and make more, when all your time has to be spent at work to survive.
Example: ya make 70k a year. Yearly expenses are 60k. Can put 10k aside. Living within your means, nice life. Yearly inflation rate is 2%. Over 5 years, your salary stays 70k. Over 5 years, you go from putting 10k aside, to putting nothing aside. Living pay check to pay check now. You have to downsize. You downsize. Again, can put 10k away, but 5 years go by, and you have to downsize again. Eventually you reach a point where to downsize is to be homeless, despite making 70k a year, or get another job.
That's a simplification, but the general fuckery folks find themselves in. Shit gets more expensive, but their salary doesn't follow. Rather the extra money of inflation going to the workers, so their salaries stay the same, the big guys get it. Their salaries actually go up, and stay ahead of inflation (salary increases by 3%), and the workers salaries goes down, staying behind inflation( salary increase by 0%). Middle class folks are finding themselves in the lower class now. Middle class is shrinking, and if nothing happens, even the lower upper class will find themselves lower class eventually.
That's an ELI5 explanation. There's more to it, not as cut and dry, but that's what's happening basically.