re: You don't understand contracting Rich. What is of more benefit success or failure when selling your services?
As to Lockheed Martin and the failures of MPL and MCO. The amount of cash coming from them was peanuts compared to the MIL contracts thus it is prestige thing and failure gave them non.
That NASA continues to use them has nothing to do with failure and all to do with them having the tools to successfully land planetary spacecraft contracts. That is both political and hardware with the needed knowledge. Others would need to run a few failed missions before they succeed. Prizes won't work in this realm of failures.
It would make sense for Launchers maybe..but not on probes.
BTW, Lockheed Martin was part of the team that would have built ARES.