The problem is that finance is not really an engineering problem. Issues arise because the techniques used to distribute risk change the market value of the underlying assets. This was a major cause of the MBS issue. Financial engineering allowed risk from MBS's to be more easily distributed. This increased the demand for these securities, which increased their value. The price of the assets increased, even though the underlying value of the assets was exactly the same. Much of the value created by financial engineering is an illusion.