Bad law can change if strongly opposed. It just seems impossible. To pick an extreme example, slavery was as old as humanity, and backed by very powerful, rich, and organized special interests, until it was strongly opposed, consistently, for decades.
It could be argued that the Industrial Revolution was making the system of mass human labor obsolete. One moneyed elite against another does not a popular struggle make.
A better example, one that was purely social, was when Prohibition was enacted in the United States (alcohol being about as old as humanity). Preachers were calling for prisons to be torn down as they would no longer be necessary with the passing of the Demon Rum.
Then again, perhaps that's not the best example either. How about we just settle on someone noncontroversial like Gandhi?
