I think there's a difference between a season lost to injury like Vinny and Chad and a team that is just terrible in its construction.
Vinny's 99 injury stands alone because 1998 was the best team we've ever had, except for (or possibly including) the 68 team none of us saw. The only team to stop us from winning the Super Bowl was Denver and Elway was retired. After that year we lost Parcells, Belichick, Keyshawn and were never the same team again. The Chad years were what they were, odd years he was hurt and we sucked, even years he was in and we made the playoffs.
As far as being historically bad over a stretch of years, again I can only point to the mid 70s and the mid 90s for anything comparable to this. The mid 70s were the last few Namath years which bottomed out in 76 when Lou Holtz came in and was fired before the last game. We went 3-11 for the second year in a row and Namath was done after the season. We went 3-11 again in 1977 with Walt Michaels but he was a new coach with a real rebuild getting started, with young players like Todd, Walker, Klecko, Harper, Buttle and Powell.
I still maintain that 1995 was worse and more depressing than 1996, even though the record was slightly better. By 96 we had some better players, played more competitive games and knew Kotite would be gone as opposed to just getting here. We also knew by mid/late 96 that Parcells and Kraft were at odds and there was a good chance we would get Parcells and the #1 overall pick after the season, which we did.
This year reminds me a lot of 1995, coach being new, except that we have a young QB trying to find his way as opposed to an aging star in Boomer. Boomer could have used some of Darnold's agility in 1995.