Why Dont Some People Learn Their Lesson?

After watching some stories on the news about how criminals get put in jail then when they get let out of jail, they go and commit crime again like if they did not learn their lesson from jail. I do not understand why criminals don’t learn their lesson from jail, even though that they will eventually go back to jail some time. Sometimes I wonder why criminals get let out of jail after a few years of being there because when they are let out, they will stat to commit crime again. Sometimes I even wonder why they have jails. I think that it would help solve crime problems if criminals were in jail for around 30 or 40 years or even for life if their crime was that bad, that should at least be enough time for criminals to learn their lesson, unless if they are in jail for life.