Actually, the Pats only drew 60K for the Bills' visit ONCE during the entire decade of the 1980s -- you guessed it, 1986, the year AFTER their Super Bowl season. 1985, the year they actually won the AFC championship? 40,462.
More fun with numbers:
The average NFL regular-season attendance total in 2008 was 66,625. (Source: 2009 Record and Fact Book.) Bills' average home attendance, for the ninth consecutive playoff-free season, and including the game in the smaller Rogers Centre: 68,996. (Source: 2009 Bills media guide.)
Bills were blacked out a couple of times in Williams' first year, 2001, yet still averaged 63,092 for those home games. His other two seasons here:
2002: 68,463
2003: 73,015
One more thought: not counting the 1987 strike season, the Bills have sold more than 500,000 tickets at home (which works out to a 62,500-per-game average) in every year since 1985.
So why do most people outside Buffalo seem to think the team has trouble selling tickets? (See Tim Graham's blog post regarding KC Joyner's latest study for an example.)