On Stanley’s point, another key element has been consent decrees — which are an even more stealthy way of regularlizing things that are irregular (and of dubious constitutionality) than bureaucratic regulations. Consent decrees can be a form of extortion. And, unlike regulations, they don’t get challenged in court precisely because the party on whom they are imposed actually agrees to them as the prices of avoiding the risk of even more ruinous consequences.
Of course, as a condition — such as quotas — is repeatedly included in a consent decree, and as it is thus actually enforced by (as opposed to having its propriety tested in) courts, it becomes harder and harder to claim convincingly that the condition is unconstitutional or promotes bad policy.