"What, back in the 50s? (I wasn't even born then)"
Up until the 70s the Lions had some decent teams. The Browns had some good teams up through the 80s. Now both are in the same miserable abyss.
The Saints turned it around, but I can't see the Lions or Browns doing it for a loooong time.
Oh once in a blue moon Detroit would make the playoffs, but I don't think they ever made it in back-to-back years. Although I did enjoy the one year with "Cocaine" Wayne Fontes at the helm when they destroyed the Cowboys in the playoffs before losing to the Redskins in the NFC Championship Game.