They could have, as could any of the other numerous organizations and comittees that notionally make up the party. My suspicion is that no electeds (or at least not enough) felt like participating, so it fizzled since the DNC doesn't really have any tools beyond "ask nicely" to herd members.
The obvious rejoinder to that is that if you're going to do it, you get your ducks in a row first and announce it with a bang. If it fizzles after that, it fizzles. But if you don't have the ability or inclination to actually do it, the solution is to just ... not do it.
Very true. Clearly went off half cocked