Anybody only paying $2 or less is probably an extra sale that they wouldn't have otherwise gotten. People who are seriously interested in buying the game would probably be wiling to shell out more, even if they don't have to.
But, that's my assumption.
Possibly, and I suspect part of the main reason why the sales figures themselves haven't been so stellar is that all of the games bar the freebie introductory one and the alphafunding title have been in previous Steam sales and indie bundles several times over. Alphafunding bundles never do particularly well in comparison.
And besides all this, I find price dumping in this way to encourage short-term profits is very damaging for their long-term prospects. Sure, they can make a cash grab for 2,000 copies à $2 and get a quick and easy $4,000, but those are 2,000 copies they will never sell again. Sure, people may be willing to shell out more, but if they see this, chances are they won't when they can get it for cheap.