There has always been British influence in America - the American government got its start with the influence of British rule, dating all the way back to the 13 colonies.
Since many monarchies around the world have now disbanded, the British monarchy is more admired than ever due to its longstanding.
Americans are particularly obsessed with British Royalty because of the fantasy element, which lies in their fascination with having a king, queen, prince, and princess.
Americans grew up with fantasy storybooks about royalty, and love seeing their fantasies brought to life in reality in the form of the British monarchy.