Of the four major American sports leagues, the NFL is generally celebrated for having the most turnover among the successful teams. Because of this phenomenon, every fan can go into the season with some hope that their team can win it all. That's even true for the teams in last place a year ago.
Since the NFL realigned to eight four-team divisions in 2002, 25 teams have gone from worst to first in their division in a single season. There were no such teams in 2024, but the 2023 Texans are a recent example.