The NFL of the 1960s was a great decade for the NFL for several reasons and just because of the Super Bowl. That started in January, 1967 but the National Football League had the American Football League to compete with, which meant a lot of great players, people who would end up in the Hall of Fame. Like Len Dawson QB with the Kansas City Chiefs, LB Willy Lanier also with the Chiefs and many others who were overlooked by the NFL, because they went to small schools. Or were drafted in the NFL but were cut there because they were behind several other players or perhaps not used. In the right way, got their opportunity in the AFL and made the most of it. It also meant that several cities that were overlooked by the NFL would get their opportunity at Pro Football. To have their own franchise, like Kansas City but also Buffalo, Houston, Denver, San Diego, Oakland, Cincinnati, Boston and Miami. Which meant the NFL had serious competition from a league, that was producing players that were good enough to play in the NFL. The 1960s was so important, because it was the decade that the NFL passed Major League Baseball as the number one Pro Sports League in the United States.
The 1960s was the last decade for the NFL that it was the league that it was always suppose to be. The last decade that every NFL franchise played their games on grass, instead of Artificial Turf, the last decade that every franchise played their games outdoors, not in indoor stadiums. The last decade where the NFL Championship was played every year in football weather, where the games were played in cold frigid weather. Championship games played in Green Bay and Cleveland in December, having to deal with frigid weather, snow and arctic wind. The NFL wasn't perfect in this decade, it was probably too brutal in some cases like defenders being able to trip and close line offenders. Being able to hit players after they are already on the ground and have been tackled and could do that until the whistle was blown but generally speaking the game was played the way it was designed to be played.
The 1960s was the last decade before the NFL-AFL Merger where the two best Pro Football Leagues were brought together and combined into the best Pro Football League in the World. The modern NFL which officially happened in 1970 even though they really already had that starting in 1967 with the Super Bowl. And it was the last decade where the game was played the way it was suppose to be played, before the game became more artificial like the fields.