As someone who's navigated their way from poor->middle class->upper middle class I can give a bit of perspective that I rarely see mentioned in these articles... One of the biggest barriers to moving up in class is the people in your starter class. Family, friends, neighbors... almost all of them will start to get very aggressive with you if you seriously try to better yourself. I remember being accused of using too…
however, if you are wealthy, you can buy an upper class lifestyle, and your children will be upper class, while you will not be.
in other words, their peers that they grew up with will accept them as upper class (meaning they had an upper-class upbringing), while their parents still consider you to be an up-and-comer, because you did not.
once you realize this, it's a much healthier situation because you stop trying to make that final jump. and once you stop trying to make that jump, both your upper middle and upper class friends will be more comfortable around you.
in other words, once you make it to upper middle, it's not worth worrying over. it's better to just focus on the money to make your family's life comfortable without worrying about social details. money defines everything under upper class; birth and upbringing defines the upper class.
by the time your children's children come around, everyone will have forgotten about you, and the new normal will have taken hold.
that last jump can only be given by birth -- which, if you stop and think about it, is exactly how it works, right?