The Social Origins Of The Brussels Propertied Middle-Classes Of 1914: The fact of having the disposal of all means of power of the establishment is not the only reason for the survival of the middle-class society. The flexible character of capitalism is attributable in the first place to a chance built-in mutation mechanism of the executive groups. Renewed executive groups adapt themselves to the contemporary circumstances more easily than a hereditary class, thus protecting the system from an undermining of its power.