The truth is this. Take the worst politician of today and tell him: "You keep your role forever. Then you pass it on to your children. Only a popular uprising might eventually topple your rule. Go govern." The result will be positive. Some will succeed and some will fail but all will improve. Why? Because there will be no need to sell government services to the electorate. The renter will become an owner. It is, for example, unthinkable that in peacetime a monarch will accumulate government debt, -- because it is his own children that will have to pay it.
We've already tried these experiments. Having the surname "Bush" basically guarantees election to high office or at least the GOP nomination. A generation ago, the name "Kennedy" did the same. I'm not convinced the results have been altogether positive.
Nepotism and political dynasties are the WORST aspects of American politics. As bad as they are now, they'd be a thousand times worse if they were institutionalized and made official.