DC has always been a fair weather city for the most part - kinda like Tampa. Win, people show up. Lose... people have better things to do on game day.
You lose all credibility when trying to compare DC sports fans with Tampa sports fans. The Rays consistently rank towards the very bottom of attendance despite it fielding a very competitive team. And during these "lean" Redskins years, exactly how many of the Skins games have been blacked out due to low attendance? Care to tell me how many of the Bucs games have been blacked out in the past few years? It's not even close!