If there was anyone with up to $50M laying around who wanted to invest it in a P2P platform, I honestly don't know why they would do so in Prosper. It would make more sense to just start a new platform. That way you would own the whole company, not just the half or whatever fraction a new investor might get in Prosper. At one time certainly Prosper had the early-mover advantage, as well as good PR. But that is all gone now. As you point out, originations are now down to the same level they were in Prosper's first few months of business. And the very name "Prosper" will soon be (if it isn't already) a negative, as it is associated with all of Prosper's mistakes. Sure, Prosper has a pretty nice website -- but big deal, I bet that could be duplicated pretty cheap. A new company would have to obtain SEC registration, but that's probably easier now that LC and Prosper have paved the way. And a new company could advertise itself as "better than Prosper," pointing out all the things it did differently to avoid Prosper's problems.
I'm not suggesting that a new P2P platform would be a good idea -- just that it seems to be a better idea than pouring boatloads of money into the sinking ship of Prosper.