Not tipping in Moscow has been mentally draining, especially when you know the gap in income in Russia. The CIA World Factbook reports that Russia ranks 49^th in the world in terms of its GINI index. I guess to be fair, the U.S. ranks 40^th, which is not that much better.
I am not by any means a rich American. I come from a family of poor immigrants who are still struggling to make it in America, and so I sympathize frequently with immigrants and those in poor living conditions. Despite my economic background, I am not overjoyed that I don’t have to do things like tip here. I feel a little guilty about it, and our group tips waiters and waitresses who are nice to us. Poverty in Moscow somehow looks a lot worse than poverty in the States, and the presence of the immigrant population in Russia is overwhelming. Sometimes Russians, very similar to Americans, are weary of foreigners. Many of the drivers of the marshrutkas (small van buses) are from the Caucasus, and you realize that Moscow is as much an immigrant city as Chicago is, if not more. There is not much of a presence of a middle class in Russia (and this might just be my misperception!), in the same sense as in America, and so I think the poverty I see sometimes in the streets and especially on the metro hits me a little more than I am used to back home.
I am more than a little worried about what will happen with the income inequality here as the Russian economy slows down.
 
Here is an article I found online that sheds some light on the situation and has good information on the current population of Moscow.