Just like over funding the police leads to over-policing, more funding for prisons would probably lead to more unnecessary incarceration, not better conditions.
Incarceration is just fundamentally antithetical to rehabilitation. To quote Danielle Sered in this excellent On The Media interview on restorative justice:
> The core drivers of violence are shame, isolation, exposure to violence, and an inability to meet one's economic needs. The four core features of prison are shame, isolation, exposure to violence and an inability to meet one's economic needs.
Incarceration is just fundamentally antithetical to rehabilitation. To quote Danielle Sered in this excellent On The Media interview on restorative justice:
> The core drivers of violence are shame, isolation, exposure to violence, and an inability to meet one's economic needs. The four core features of prison are shame, isolation, exposure to violence and an inability to meet one's economic needs.
(https://www.wnycstudios.org/podcasts/otm/episodes/on-the-med...)