I think you have that backwards. They exist to preserve privilege for legacy kids. They let in some of the best and brightest so that some of the prestige from their accomplishments rubs off on the legacies.
If only that then it’s a dysfunctional system. Ideally it’s a mechanism to recycle elites. Preserve elites that are of a certain quality, dispose of the low quality, and acquire new elites from the pool ensuring a high quality of elites that is not only tied to ancestry.
The cynical view is existing elites only steal from the best from the pool. I’m not sure empirical evidence supports this. The system probably over-selects existing elites. But it’s their system. I’d argue that AA was a tool to allow even more over-selection and preservation by consuming seats with unqualified and therefore uncompetitive quotas. Cultural cachet I guess and a moral justification for low quality elite preservation.
The cynical view is existing elites only steal from the best from the pool. I’m not sure empirical evidence supports this. The system probably over-selects existing elites. But it’s their system. I’d argue that AA was a tool to allow even more over-selection and preservation by consuming seats with unqualified and therefore uncompetitive quotas. Cultural cachet I guess and a moral justification for low quality elite preservation.