I'm the author of the blog post, but the claim of success is based on a number of factors other than the $1.
As we note re the $1: > "This unexpected development will no doubt force us to rethink some of our assumptions about the reverse-auction model."
Also, the success is borne out of the data: > "Given these statistics, we think it’s fair to say that there is a market for open-source micro-purchasing, though we obviously will need to spend some time and effort refining our methods.
The success is in validation of the idea, not the actual result in this case. That said, the result is new, functional open-source software for the American public. So that's still a pretty good outcome.