To stay in power, every leader needs some contingency, even if he is a dictator.
Putin is still doing what he is doing because the mentality he represents has the support of:
Those Russians in Russia who are derailed from reality and either have no opinion of their own or are afraid to express it. They have lived with the "tzar" in their head for generations and have problems adopting to any other reality.
Part of Trump supporters in this country that are capable of trading the very idea of democracy for the lies spread by a demagogue and don't trust democratic institutions or believe in the power of law. This is how it begins, watch the news to see how it ends.