The most cogent analysis of the film I've seen is that it's basically a film about how cinema is realer than reality.
The big clues being that Shoshanna is only shot because she has a moment of empathy for the Nazi fuck that got her the gig for the cinema, but she only has that moment because the film she watches sympathises with him and the British spy not being rumbled by his ridiculous citation of a german film to describe his family, but something you'd never pick up from a movie - the fingers you use to indicate a number.
Thing is, the Shire was a hereditary monarchy, they just didn't call their ruler a king - it was Thane. Pippin was in line for and did eventually inherit the title.
There's also Buckland, the small offshoot of the Shire ruled by the Master of Buckland, and of course this title was inherited by Merry.