(a) "Peer to peer" credit - managing the bilateral creation of "trade" credit necessary for the creation of productive assets, including the bringing together of risk-friendly investors with risky development;  

does not describe exactly what was done by investment banks when they put together groups of mortgages (risky development) with bond buyers (risk-friendly investors) - by setting up various tranches with different risk profiles, they allowed buyers to take exactly the risk they cared to; by making the market in MBS highly liquid, more house buyers were able to find funding for their projects.

It's conceptually substantially the same thing.

In the long run, we're all dead. John Maynard Keynes