The obviously fun takeaway would be that if we put North Korea as a 9 on the Dear Leader scale, and USSR under Stalin at 8, then the USA will rate 4 its President cult, and that would be much higher than the rest of Western world.
That's the essential genius of constitutional monarchy - by investing the royal family with immense status but no actual power, we reduce the status of those who wield real power to mere public servants. The Prime Minister must ask the monarch's permission to form a government, in the knowledge that the monarch has no actual power to refuse. Those who hold public office swear an oath of loyalty to the monarch, in the knowledge that the monarch's power is wholly and irrevocably delegated to parliament and the judiciary.
The monarch is in essence an empty vessel, symbolising whatever version of Britishness we happen to believe in. Regardless of the government of the day or the divisions that may arise in society, the crown endures. The man or woman responsible for running the country does so as a temporary custodian.
Britain is dysfunctional in all sorts of ways, but the parts that function best are extremely Lindy. The monarchy, like our unelected upper house, is completely idiotic in theory but incredibly successful in practice.
But is what you describe a good thing? People seek status. By removing status from being Prime Minister you make being Prime Minister merely another step on the path to status. I'm not sure it's a good thing for someone to see being Prime Minister as a means of leverage to something else they want.
The UK deal with the royals is really quite different. There may be an over-fascination but there isn't a huge amount of deference, and if the royals want to make things happen that are not popular, they have to use very twisty back door routes. The (public) relationship that even fervent royal supporters have towards the royals is nothing like the (public ) relationship with Stalin et al.
Also, it's pretty easy in the UK to say that the royal family is stupid and they suck and they leech money from working people and nothing will happen.
The USA managed to do something special: replace the cult of personality with the cult of the Party. There are two parties, but their followers are quite rabid and would probably kill for their party if told to. So if we expand the criteria for "dear leader" to include parties I think the US would be at a 7 or 8.
If this was the case there wouldn't be so much hagiography for any given president or presidential candidate.
I also think a 7 or 8 rating is way too high for the US even on a party level. A 7 or 8, given the Kims are a 9 or 10, would probably be more along the lines of a Xi (observing that former heads of state of China have been unceremoniously retired, which shows that personality only goes so far even in an effectively single party structure).
There are people who won't talk to anyone from the political religion opposite to theirs. Both sides call each other Nazis. And they'll vote for a candidate from their party even if the candidate would have to rule without regaining consciousness before they'd consider the other party. I think that's a pretty extreme level of brainwashing.
Yes, but you'll find rabid rabble rousers in spectator sports as well. While this may say something about the polarization of the parties, it says a bit more about individual and group psychology. And doesn't say much at all about the organization of power in the US.
Is that a good thing? A bad one? Who knows.