The greater the area occupied by the same number of inhabitants, the more difficult it becomes to revolt, since concerted action cannot be taken promptly and secretly.
Gist of Idea
If inhabitants are widely dispersed, organising a revolt is much more difficult
Jean-Jacques Rousseau (The Social Contract (tr Cress) , III.09)
Revolutions since then have all occurred in large cities, which have become huge. The dispersal of the rest of the population (as in Russia) doesn't matter.
Rousseau,Jean-Jacques: 'The Basic Political Writings', ed/tr. Cress,Donald A. [Hackett 1987], p.190