The work is meant to give them a routine and responsibilities. As they would have outside of the prison. Many prisons have the option to forego work and pursue education as well. I'm sure some prisons are not like this, but not all.
As others have pointed out, targetting recidivism rates would probably be the best way to tackle this problem. This means things like not allowing for discrimination on employment opportunities, a right to be forgotten, among other things.
Getting out of prison and being unable to secure a job is a huge problem. Of course they will go back to crime. It's not like going to a medium or low security prison is anything more than adult summer camp anyway.
Most prisons bait people into work via a combination of carrot and stick. Prisoners often lose privileges when they don't work, parole boards look very unfavorably on declining to work, and many prisons force prisoners to buy basic things like toothpaste and deodorant from a commissary out of their wages. Not working is not a reasonable option in the majority of cases.
Sounds like life in general frankly. There's also typically a heavy religious influence within prisons including helping people out with necessities. It's complicated.
That's not to say it is perfect by any means. I have friends who have been to prison that form my opinion and what impacts them most is not the prison but the society around them when they leave. They get passed over for jobs and end up on social assistance, social housing (when your rent cap is $376 and average rent is $1200 for a bachelor and your basic needs amount to $300 assuming you get some special diet).
As others have pointed out, targetting recidivism rates would probably be the best way to tackle this problem. This means things like not allowing for discrimination on employment opportunities, a right to be forgotten, among other things.
Getting out of prison and being unable to secure a job is a huge problem. Of course they will go back to crime. It's not like going to a medium or low security prison is anything more than adult summer camp anyway.