The brain drain is a huge negative. This is the biggest miscalculation he has made. He'll probably be forced to contain it by making exit visas difficult, effectively turning Russia into a prison. This would make him a dead man walking. His own people would definitely get rid of him.
The big difference is that the younger generation of Russians has experienced the modern world. They've also seen how easy it was to get rid of various dictators and autocrats, e.g. the ones in Romania, East Germany and Libya.
The brain drain is a huge negative. This is the biggest miscalculation he has made. He'll probably be forced to contain it by making exit visas difficult, effectively turning Russia into a prison. This would make him a dead man walking. His own people would definitely get rid of him.