Speaking as a Russian myself, I find the OP silly.
As MMA becomes more popular and established, what we've seen is the opposite of any one nation or region dominating. Rather, we've seen more excellent fighters from a greater number of countries than ever before.
In the early years, there was Brazil, the USA, and in a distant third, Japan. Then, around the 2000s, we started getting good fighters from Canada, Russia, and the UK. Nowadays, we get elite level fighters from a dizzying array of countries; Australia, New Zealand, Germany, Poland, Ireland, South Korea, Mexico, Cuba, China, Ukraine, Philippines, etc, etc.