Why do you assume racists are economically rational?
Yeah racism is larger than matters of individual prejudice, but I don't see how racism is meaningful as a category unless you can locate it in specific human acts and relationships. Sometimes it sounds like phlogiston.
Doug
^^^^^ CB: A major component of structural racism is residential segregation. The specific human acts that established the post-Jim Crow , neo-segregation residential pattern was white flight from "center" cities in the 50's, 60's and 70's. So, the individual acts are no longer going on. They took place "long" ago , and established a residential structure that functions today "passively", without as many "active" human acts.
Other aspects of structural racism have this passive character. Building trades jobs tend to be passed on through families, so no breakthroughs for large numbers of Black construction workers occurs passively. Same with differences in the bell curves in IQ, education or income. All that has to happen is to retain the status quo, that is non-action ( non-affirmative action , to be specific) by humans will sustain the racist structures and disparities and relationships. Most individual white people don't have to do anything racist for racism to persist. They can spend their whole lives being non-racist in their actions ( even vote for Obama) , and racism will stay in place.