Your assumption is false.
In more than 40 years of working life I have run across no more than four or five people that I knew got their jobs through connections. I have seen some people advance on brown-nosing or wearing senior management down until they got promoted, but most people advanced on merit and were competent to handle their new positions.
I ended my career last fall with a very well-paying job, but it took me 25 years to get there. Until 2000 I was never paid much more than average for my job title despite the fact that I was consistently rated a top performer. I didn’t work for big-bucks companies until the last decade.
But I never thought I was unfairly treated, and I never made up fictions about other people and their jobs to explain my own dissatisfaction.
My son is a deeply decent, honest person who has just begun his career as a lawyer because he wants to make the world a better place. He doesn’t expect to make a lot of money, and that is fine with him. I believe that he will end his career the same way, even though I won’t be around to see it.