The Wikileaks dumps did create stories over the course of several weeks and several outlets reported on them with regularity. The problem was that the vast majority of cables were unimportant, uninteresting or gossip.
If anything, what we learned from the Wikileaks dump is that if you want to look like a whistleblower and not just someone trading in state’s secrets, you need to limit your leak to just the illegal bits. Given the size of Snowden’s cache of papers, searching for just those illegal bits takes time which is almost certainly the main limiting factor in the speed stories are coming out.
