If you're a high school wrestler in the US and you aren't in excellent shape, you either have a dog shit coach or you're cutting corners...big time. Wrestling practice is no joke. Every year, we'd have a couple kids who played football try to wrestle for the first time. You'd always tell them that the training is very different and they're in for an eye-opening experience. Almost every time, you'd be met with some pushback about how great of shape football put them in or how we were exaggerating and almost every time, they would be completely fucking dead by the end of one practice and mentally broken.
Wrestling separates the men from the boys. Period.
You bring up a great point I never mentioned. At the beginning of the season we have around 30-35 guys, after the first practice a few quit, then the first week half the team is gone. I'm not joking when I tell you WRESTLING IS HARD WORK. We'd even have red flag days where all we did was condition for 3 hours. The worst was line days, where we would run sprints across the gym for 3 hours.
I'm not trying to categorize all football players but from my experience they all quit besides one (our heavyweight who won state ,but he also wrestled in junior high). They come in arrogant, thinking because they lift they can dominate everyone, and they usually quit a week later.