Putin is an el supremo type of dictator, a supreme networker for 25 years, who has tied many onto him. Via threats, kindness and money. If Putin croaked tomorrow, his successor would not be able to hold Putinist Russia together.
Ramzan Kadyrov, don't be surprised if he tries to seize Moscow after Putin dies. He has an army of Chechens that report to him. So if there's a power vaccum, he might seize the opportunity.