Because he is the one who still lives the life of Kadafis, Mubaraks, Husseins of the world and he witnessed how they ended up during these years. His neighboring states like Kyrgyzstan, Tajikistan, Georgia, Ukraine are too constant reminders of the fate awaiting certain presidents of the former Soviet Union states.
If you still don't quite understand how Putin consolidated power inside Russia just look at the party representation across governors of Federal Subjects in Russian Federation. Then compare with similar governments of States in Germany (both are federations according to their constitutions). United Russia ("Единая Россия") is party Putin represents (even though he is formally nonpartisan), and nonpartisan governors are de facto proxies of "United Russia" in most (if not all) cases.
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