It's not a guarantee that the new one will be better - it's the guarantee that the new one will be not the old one :) . As an example, Boris Yeltsin was a diffe

It's not a guarantee that the new one will be better - it's the guarantee that the new one will be not the old one :) . As an example, Boris Yeltsin was a different kind of a leader. Of course, the idea is to prevent people from the same circle - with similar or worse ideas - to have the power. Robustly that's to be solved by the people of the country - who apparently suffer from lack of learning on the previous mistakes. Also, getting best solution takes longer time... to the initial results.