Why would Amazon want to give this data away? If somebody else can use the data better than amazon, they'll probably steal the sales from Amazon too, and amazon loses out.
Amazon appears to be under the belief that retaining customer trust is much more valuable than selling customer data for immediate gain.
I suspect it has to do with their unique financial setup that allows them to operate with a long-view, and not have to chase quarterly profit.
Tracking people makes them :(