Traditionally the upper class made a living based on what they owned and the lower class (barely) made a living based on the work they did. There were nobles an

Traditionally the upper class made a living based on what they owned and the lower class (barely) made a living based on the work they did. There were nobles and serfs. Labor and capital. This distinction worked for many centuries. The rise of the middle class is a modern phenomenon, whereby a new class was created who still essentially worked for a living but were able to achieve a measure of security and prosperity that led to a dramatically more stable society. Of course that development has caused some consternation within the upper classes, who are presently trying quite hard to roll that back.