Prison in the US is less about controlling felons, and far more about controlling the rest of the population.
You have to ask why there are so many offenders in the first place - that’s a question for you to answer - but I suggest the huge wealth disparity, opportunity disparity and extremes of health, education and inculcated expectations of every US citizen are all likely to be contributors.
Once you have some sort of handle on why there are so many offenders then maybe you have some way to decide how to prevent young offenders joining.
In effect what you have is an underclass, they have little expectation of a regular life - but they do know they should have all the benefits they see advertised on TV.
I expect the US culture of individualism, and especially the worship of the bad boy image are both contributors - lets face it, gangsters are all utter scumbags - but they seem to be worshipped through rap music, and its an old tradition dating back to the war of independence - scumbags who rob and raid and murder being idolised as ‘good old boys’.
We have tv shows idolising moonshiners, smugglers, and marijuana growers. It really does not matter what your personal views are on these things - the damaging thing is the worship of criminals, decriminalisation is simply a fig leaf for those who wish to take part in the bad boy values of these scum.
When offenders are released, do they have mental health support, do they have the trade skills and work ethic? Nope, many need support for addiction issues, and almost all will return exactly to the same circumstances prior to their incarceration - is it any surprise that they return to prison?
Rehabilitation is extremely expensive, this is because it requires extensive supervision in society, it requires employment, housing, counselling, training, it requires former offenders to kill their former lives and never associate with former friends, often their criminal minded families and this needs incredibly close supervision, did I say it needs close supervision? This is extremely expensive, did I say it was expensive?, Oh Yes - but is far less expensive that the current situation, where each generation of criminals inspires and trains the next generation of criminals.
Also, do not forget that in terms of economic output - these individuals who contribute nothing to society actually consume resources that would be better directed elsewhere.
No politician in the US is likely to stand on a ticket of spending more on rehabilitation per offender, nope, that’s a waste of tax dollars. Why do you suppose this is the case? Could it be that you have a revenge culture? Could it be that the political argument is how to appear macho?
Maybe its also because the majority of offenders are from black and Hispanic communities - and who cares about them? Little Johhny white boy gets his and that’s all that matters.