Russian brides get married to have a happy family for themselves, because this is their highest value: a Russian woman needs her own family, a husband and a child/children, to feel happy.Cultural values are deeply ingrained in any person; most of us have no idea of those values or never spelled them out.
It means 12% of women have no chance to find a husband or be married. Second reason is the well-publicized alcohol abuse in Russia by men, which results in poor health conditions and abusive behavior of men.
It is a custom where men get together in groups after work and get drunk, then go home.
Yes, most Russian women work (and were always working since the Communist Revolution in 1917), there is still plenty of male chauvinism and since men occupy most powerful positions, they don't want it changed!
I would have never even considered leaving Russia to marry a foreigner if I could meet a good man in Russia and get married to him and have a happy family. This is the fundamental difference between Russian/Eastern European women and Asian main order brides, as I see it (I may be totally wrong here, it's just my personal opinion): Asian brides consider immigration as the means to support their families and provide for their parents and siblings, and I know husbands of Asian brides have to send money on monthly basis to support the wife's family overseas.
My feeling, this is the reason why most Asian brides get married, to provide for their families.