The importance of the middle class relies in the fact that people who feel they belong here have a certain degree of autonomy without being entirely detached.
They have enough ‘substance’ as not to be in abject dependence on their ‘masters’ but  they don’t consider themselves  so wealthy as to be impervious to anything.
In fact the ‘middle class’ are the only people who really care about the day after tomorrow, the dirt poor are too focused on surviving till tomorrow while the ‘filthy’ rich are not concerned with such mundane things…