Where the `masters of he universe' went wrong, is they dressed up complex financial instruments(ie sub-prime mortages) as great things to invest in.
It appears that they may have violated a economic law, namely they were not producing any product or service.
If everyone were dealing in dirvaives ,socks or shares etc with the idea that is how to make your money,but not producting any goods etc, you wouldn't have any people making wealth from goods and services.
Greed can also bring down an economy.
Perhaps someone should have helped these sub-prime morttagees by training them for high quality jobs, making it less likely that they would default..