Scientists hypothesize that there are no dinosaurs alive today because

a. an ice age froze all the dinosaurs
b. they were all killed when a large meteor hit earth
c. they could not adapt to a new environment to avoid extinction
d. mammals out-competed the dinosaurs for food and living space.

you did not attach the discourse, but i assume it to be the discourse on the origin and basis of inequality among men (the original titile in french is: "discours sur l'origine et les fondements de l'inégalité parmi les hommes"), also know as "second discourse". in this discourse, jean-jacques rousseau emphasizes that private property is the basis of all inequalities.

therefore, what enabled the old regime to maintain as long as it did was private property.