From what it seems, D.C. likes baseball — they've just never had a good team of their own. Two franchises known as the Senators relocated to Texas and Minnesota. The team they were gift-wrapped by MLB in 2005 was the itinerant Montreal/San Juan Expos, the team nobody wanted. They were FINE with this. Hell, they even built them a new stadium, mostly because they didn't skip town and head for Portland or Vegas or Birmingham or anywhere but Washington.
But mere baseball isn't enough. A fanbase needs a catalyst, someone to excite even the casual fan. Your purists might appreciate the commitment to winning by signing Adam Dunn, veterans Pudge Rodriguez and Livan Hernandez, and locking up infield captain Ryan Zimmerman to a long-term deal, but a "commitment to winning" doesn't translate to the more important fan's "commitment to giving a shit."
As Grilli mentioned, Fidrych's magical 1976 season was otherwise miserable for his Detroit Tigers. He had a record of 19-9. His teammates were 55-78. The team finished 24 games out of first place. But nobody remembers any of that. The summer of '76 was the summer of The Bird. And '10 may be Strasburg's Summer, although the National League East may go to the Phillies or Braves. But 30 years from now, who shall look back on that division title?
In the end, baseball memories that traverse generations may not be measured in Major League Baseball's annual revenue report or Strasburg's career numbers, but they're equally real.