Isn't your premise only true if it's impossible or very hard (in absolute terms, not relative to rich people) for poor people to get richer? "Feudalism," while

Isn't your premise only true if it's impossible or very hard (in absolute terms, not relative to rich people) for poor people to get richer? "Feudalism," while not being very well-defined as far as I know, implies that the lower class has a low quality of life.