Although economics began with a side of morality the implementation of science as a replacement is something that does make sense. That is to the effect of saying it is constructing better models of and making better predictions of changes in the economy. That said, morality in economics did play an important role when it was introduced many years ago. I believe that the reason it did is because in the early stages of economic introduction most of the people had rather common moral beliefs. Now, this would have resembled a code to live by or something you could govern yourself by. Therefore, morality in economics back in these early times would have been somewhat of a science for the people. In todays world there isn't a very straight forward set of moral beliefs. This is because I think many confuse morality with law. Perhaps they believe something to be bad more because it is against the law and less because it is morally bad. However, many religions institute moral guidelines and codes in which their followers are supposed to live. So, perhaps mini economies within churches are the modern example of economics and morality. It is not scientifically proven that giving money to a church collection will give the giver benefits yet the people of the congregation still give. Whats also interesting is the donations tend to be pretty steady and the economy of the church gets by on money individuals are not required to give yet their moral code compels them to because they believe in the benefits the church is providing. In terms of America morality and economics would not work because of our population diversity. We have people of all religions that have many different moral codes. There are also many who do not get their moral code from religion at all. This isn't to say that not having a moral code based from a religion is bad or good but simply to say that when someones moral code is not structured on a belief system it in tern becomes nearly impossible to predict.
The new economic system based with science is most certainly a better fit for todays world. That said morality and economics could serve as a much better economy for people who have common beliefs that they govern themselves by. In America though there would be too much controversy and the result would be a very unstable economy.