The “Grand Poobah” assertion is a stretch at best. Using the Flintstones as a reference source is laughable
The name is commonly used as a moniker for the “big cheese”, “king” and whatever other egotistical names are out there based on my lifetime experience.
Yes but the first usage of the term “Grand Poobah” was in the Flintstones animated television series during the early 1960’s.