In a way, yes, citation is needed for the claim. But citation is not needed for policy. Predicting individual's "value" to society and granting/restricting opportunity based on that is not only hell of a slippery slope, but absolutely anti-thetical to democratic civilization. It's quite literally what both the fascists and the nazis did deliberately.

Every society has both codified and unofficial deviations from the principle of "equal opportunity". For instance, insurance providers that are allowed to discriminate based on age, among other factors. But giving up on the principle explicitly is a different beast.