Here's a very relevant paper on the issue, where the researcher concludes a number of suggestions, including "we need to consider ceasing to use prison as punishment" and "we should draw on the research of what we know works to prevent recidivism, especially literacy programs, skills training and GED, as well as educating prisoners to associate’s degree level in higher education and restore financial support for these successful practices": https://www.researchgate.net/publication/258834307_On_the_Ef...
> spending time in jail for... stealing a pack of diapers?
That's disingenuous at best. These people steal hundreds of items and setup tables selling them. This isn't a mother stealing formula or diapers for her child. It's a criminal operation stealing stuff by the trash bag (as we have seen in many videos over the past few years) in cities with very loose theft laws (mostly on the west coast).