I was taught by my Literature professors that Russian novelists did it, at least in part, to make their books more timeless, as location names were known to change depending on who was ruling. Street names, buildings, etc would change also depending on if they were named after someone and how that person was perceived at the time...a well-known example would be St Petersburg, which was Petrograd and then Leningrad, then back to St Petersburg. Only on a pettier level of changing names...(I mean, I think there are probably multiple explanations. This is just one.)