https://en.wikipedia.org/wiki/Tuskegee_syphilis_experiment

There's this narrative that the major cause of improvement in conditions (civil rights, workers rights, child rights etc.) comes from government regulation. This is called legal prescriptivism. Another narrative is that things generally improve as the economy does, and are then codified into law. This is legal descriptivism.

Typically history moves forward with a mixture of both, but it should not be taken for granted that prescriptivism is always the only way progress happens, nor that prescriptive progress always positive.