Former Editor-in-Chief Ryan Avent writes a weekly column about neighborhood and development issues. Things used to be clearer for Fairfax County. It used to be known as the epitome of upper-middle class suburbanity, even earning name-checks in popular novels and songs as such. With acres and acres of rolling hills covered in leafy suburbs and landscaped office parks, it was a quiet complement to the quirky inner suburbs of Northern Virginia and the dense chaos…