I don't think NOVA had blow up quite enough yet to flip the state, although there's also another question as to why John Edwards couldn't inspire more working-class rural voters in the state.
You say that as if much of the area didn't vote for Bush too but was simply outvoted by the rest of the state. NOVA is not the same place that it was in 2004.
Interesting to note that Fairfax County - Virginia's most populous - voted for Kerry in 2004 despite having voted for the GOP since 1964.
In retrospect, Dubya in 2004 seems like almost the perfect candidate for NOVA - his folly into Iraq was major cha-ching for defense contractors and the local economy, after all.
Its hard for me to fathom why NOVA would have swung to Kerry in 2004. There's a strong military presence in the area, heavy reliance on the defense industry, and the area was directly impacted by the 9/11 attacks (similar areas in NY/NJ swung heavily towards Bush in 2004). It would seem like "security moms" here would have gobbled up Bush's anti-terror rhetoric and responded to the anti-Kerry attacks.
Maybe this dilemma points to a more fundamental shift in NOVA's voting patterns, a shift that eventually resulted in Democrats being able to carry Virginia somewhat comfortably ever since 2004. Perhaps in that sense NOVA in 2004 was already what it is today, just smaller.