I'm guessing here but since it's a re-packaging of Sony's previously-released sets, they're probably looking to obtain some sales from the collectors that didn't buy the earlier single-season releases or the bargain-hunter groups.
Dave Lambert posted about an entire-series release at TSoD here
Release date 10/15/13 at $55.99 SRP.
One part of Dave's post would probably be a split decision on whether it's a pro or con point for anyone interested in picking up the series at a great price:
The first 2 seasons in the box...