Maybe the cherry trees in DC are not so hardy? And they may be just for the blossoms. I have not heard of anyone picking the cherries
Michigan has counties devoted to cherry growing and they market them as healthy and a gout cure. Michigan has the harder to find sour cherries
The cherry trees around the Tidal Basin are Yoshinos, Punus X yehodensis. They rarely have fruit and are one of several types of Japanese flowering cherries. Even the cold of this relatively cold winter in DC should not bother them as I know there are cherries of this type growing in the metro NYC area.
The biggest threat to the blossom display is actually a late frost.