It doesn't really add up. The schedule was always uncertain. Why not postpone? Why a big announcement only a year and a half ago? Seems pretty cruel to all the people selected to take the trip...
Probably all the explosions and bad reentries in the timeframe when he was supposed to already be launched gave thoughts of the Titan submarine. When he first signed up it was supposed to have something totally different for the heat shield, transpiration cooling or something.
Plus tying your money up at 0% interest rates is different than at 4.5%.
