Leeman Bennett, Dom Capers, Monte Clark, and Herm Edwards only lasted 8 years.
Marion Campbell, Walt Kiesling, John McKay, Bruce Coslet, Bart Starr, and Dick Jauron are the true rarefied air of having a career nearly as long as Vince Lombardi and Bill Walsh and producing nothing. That is not good company. [Edit: of those guys, Jauron could catch and pass Bart Starr this year. McKay has a good excuse. He coached the expansion Bucs. Kiesling coached during WW-II.]
Wayne Fontes, Steve Mariucci, Ron Meyer and Jerry Glanville have better records.