Cherry picked the time period when then were very good...but what happened after that run?
Oh yes, a string of four consecutive non-playoff seasons each either .500 or below. After that? Make it in '90, out in '91. Make it in '92, out in '93. Make it in '94 and '95, out in '96. Run starts in '97 ends in '01. They '02-'07, make it in '08, then out again '09. Off and on since that run in '85
So once that run up to '85 ended they were out of the playoffs ten years and watching the playoffs 14 years.
What did Buffalo do in the 20 years between the demise of their '60s powerhouse and the rise of their '90s powerhouse? Three playoff years and 10 losing seasons. What have they done since then? They missed the playoffs 10 consecutive seasons with only one of those seasons getting above .500