I agree with the fluidity and that's why this project was fun to watch to see how voters determined who they thought were stars and their actual belief at what a star actually is.
Regarding Thesz....he was the NWA champ during the middle of the television boom of the early 50's when wrestling was up there with baseball, boxing, & horse racing as the major sports of the era.
Gorgeous George may have been the top star overall but Thesz was the contrast and right there behind him.