It's unique in sports. Nobody ignores Babe Ruth, Lou Gehrig or any of the other early greats.
The only exception is Jim Brown. Otherwise the NFL criminally underplays it's pre-Super Bowl era.
As far as the AAFC is concerned -- the Browns drew better than ANY other team in the AAFC OR NFL. The AAFC owners had more money and great players, but they didn't have a draft so Paul Brown sucked up tons of talent. The NFL made fun of the AAFC and then got CRUSHED in the REAL first "Super Bowl" between the Browns and Eagles in 1950 (defending champs).
Otto played 10 years, 10 championship games, 7 championships. That team is the ONLY team in NFL history to play in the NFL championship game SIX years in a row. Oh, and Otto won a pro basketball championship as well.
Plus Cleveland won the NFL the year directly before the Browns' run -- 1945 Cleveland Rams. They pulled a LeBron and went to LA and took Bob Waterfield and his wife with them. Lou Groza then beat their west coast asses in Cleveland Stadium in the Browns first year in the NFL with a 16 yard FG to win it with 28 seconds left.
Waterfield's wife: