No one could have warned the Quakers that, by replacing capital punishment with prisons, they were establishing a punishment that can be worse than death. The introduction of the indeterminate sentence, with a parole board deciding on a release date, was intended to facilitate the process of rehabilitation. No one warned the policy makers that the indeterminate sentence would result in virtual life sentences for individuals whose crimes aren't necessarily serious but who can't adapt to prison. Parole boards become political tools of politicians, who, in turn, are guided by popular opinion, formed via the media. No one warned the reformers that with every reform the prison is reentrenched as the dominant response to social problems.
Punishment is taken for granted.
Everything else is an alternative. In the United States, at the current rate of increase, in 30 years half the country would be imprisoned and the other half would be guarding them. It's an untenable trend. Most seriously, no one warned early advocates of alternatives to prison. Home confinement, wearing bracelets, was seen as a decarcerative measure, to reduce the numbers locked up.