There are attempts to re-integrate ex-convicts back into society, and prepare them for that re-entry while still imprisoned, but...
... the effectiveness of that has been pretty consistently poor. I'm admittedly unsure what exactly all the major issues are.
Among the definite ones, though, is the fact that the majority (or at least a large minority) of (US, or at least fairly large swaths of it) society simply doesn't see rehabilitation as the purpose of imprisonment. To these people, criminals are scum and are 'getting what they deserve' (Note: There is often an effing huge dose of hypocrisy involved here.). Prisoners are not imprisoned to learn and improve and prepare themselves to come back and contribute to the community, they're there to suffer for the wrongs they did, after which they will suffer more by being shunned from gainful employment and decent standards of living. There's progress and in-roads here, but there's still seriously major problems.
Implementation also seems to be a pretty big issue. A lot of folks trying to push through rehab and reintegration still aren't entirely sure what the best way to go about it is, and failure can have some pretty hefty consequences, so progress is slow. The logistic/mechanics part of the issue falls in here as well, as the US has an absolutely tremendous prison population and it generally takes a fairly well trained individual (or more likely, a fairly substantial number of said individuals) overseeing the rehab process to actually get anything done.
In short, it's a, as they like to say around here, melluva'hess.