Earlier quoted context omitted.
Russia is bigger in terms of area, just two times smaller in terms of population, but 10 times more uniform, at least. You wouldn't be able to tell apart two typical provincial Russian towns from the opposite sides of the country. So, no, just the size itself doesn't seem like a complete explanation for this.
U.S. divisions at this point run largely rural versus urban. Russia has the same thing - folks in Moscow live completely different lives than those in a backwoods provincial town. If anything, Russia and the U.S. are pretty similar in terms of regional and cultural tensions.
Not really. I live in Moscow, and financially I have a very different life from someone in a small town. But in terms of the culture and people around, the difference is not that big.
Here's a random youtube vlog about a small russian town: https://www.youtube.com/watch?v=QOwW5wdIt_w It's on the opposite edge of the country, and yet, I would only be able to tell it apart from Moscow's residential neighbourhoods by how tall the buildings, built from the same panels, in the same design series, are.