I think you hit the nail on the head there. I have friends who have lived in DC since before the beginning of the H St renewal project, and the change that I hear over and over from them is one of accessibility. People never visited the few businesses that struggled to stay alive on H St because getting to them by public transit was nigh impossible. Certainly many gave that area up as a lost cause - but with the combination of focused redevelopment and the addition of the streetcar it now has new businesses opening every month and an energetic feel to it that draws people in from all over the metro area.
Certainly this sort of transformation can take place in areas with such potential as Euclid Ave!