Normally during revolutions, some other worse assholes fill the power void and sieze power. It happened with the 1917 revolution who gave us none other than Stalin. Or the French revolution, which triggered a series of wars and then we had Napoleon filled that power void and started some more wars.

The 1989 revolutions are somewhat different, because they were triggered by the colapse of the USSR, so to some extent a peaceful transfer of power happened. Except for Romania, Moldova and Ukraine who is now paying the price for refusing to become the other Belarus. The collapse of the USSR ultimately led to Putin the wars in Chechhnya, Georgia and Ukraine.