Actually it was the 70's AND 80's Bills.
In the mid 70's, the Bills were in a bad funk. Winning 2 and 3 games, playing in a relatively new Rich Stadium, and drawing 30,000 to 40,000 a game. Ralph went all in and brought Chuck Knox in from the Rams. It was a huge move the gave the Bills credibility again and the franchise had did better and fans came back.
In the mid 80's the Bills had two back to back 2 win seasons. Fans were staying away from the stadium like they could catch the plague if they went. People were also driving around WNY with bumper stickers that read "bring pro football to Buffalo". Ralph, in his own words, decided to get serious again and stop hiring friends to run the show and handed the keys to Bill Polian.
Now, look at the Bills in the last decade plus. For the most part, great attendance. No need to make serious changes.
Fans can have an influence on a professional franchise.