Nah, I just can’t buy it. Unless you are referring to the coaching staffs, high school roster turnover does makes me a doubter in any type of “mental block.”
Now, if you wanna talk overconfidence I am all ears. When it comes to Homestead, maybe they got comfortable being the best team in their backyard and it gave them a false sense of accomplishment?
Just spitballing here but I also heard the same idioms and tropes being tossed out about the Big Ten against the big bad SEC for years.