Where have you been the last 16 years? ED makes mostly Russian aircraft because they can get their hands on manuals, pilots and other personnel that will provide the needed info and experience.
How do you know the customers in the 'USSR' (Hi there comrade MCP) are happy with ED's service? The Russian forums are also full of 'F-15 lacks this, we need realistic Vikhrs, the A-10 is too sluggish' kind of whining. If any, it's worse over there, as the F-15, A-10 and the 'Soviet' aircraft are all bad, and everything is not moddled correctly. Here all we hear mostly is the F-15 whining.
Oh, think of teh time zones, and how many people speak Russian. Then think about how many are taught English from the cradle, even though it's not their native language.