When my son was in HS (band nerd, not football team, but I went to the games), the football team got their butts handed to them every year by three strong teams in their district. A good year was when they beat the two other teams in the district. They never had better than a 3-7 season.
Then when my son was a junior, they got their butts handed to them by one of the strong teams, making them 1-4 on the season so far. The next week was Homecoming against the second strong team. In a muddy mess of a rain storm, they came out ahead, 10-6. The following week they played the third strong team and.... beat them too. They didn't lose for the rest of the season and won a state championship (this is Texas, mind you).
But only by being challenged did they get any better.