This same over simplistic view is used to explain why Russia expanded so aggressively to the west and east, and holds its client states so tightly.

There is a nice grassy plain from Poland all the way through to the Caucasus (with the Urals as a somewhat permeable barrier). Armies on the move love grassy plains.

If your objective is to protect Moscow, you need to control that grassy plain.

Edit: ref: Prisoners of Geography: Ten Maps That Tell You Everything You Need To Know About Global Politics by Tim Marshall.

"Geography is destiny" can be a useful lens through which to view global politics.