Rikers Island prison or jail is probably the size of a lot of prisons in big states. And part of that has to do with the fact that New York City is a city of 7.5-8M people, a size of a big state in America. Not a place any good and free person would want to go to, meaning Rikers Island, which is why we should never put ourself in a position that would land us in a jail/prison like that.
But what Rikers is in the business to do, is to house defendants. Who are awaiting trial as well as inmates who are doing short sentences. Rikers does a very good job of. The inmates who behave themselves and have good records, are able to work and go to school as well as work on their own cases. And they can go to religious services if they choose to, as well as other rehabilitation services.
Self-improvement services including drug treatment, which is a big reason why we have so many people in prison in this country. This is not just a jail where people are simply warehoused. But a place where they can make good use of the time that they do there, which should be purpose of jails and prisons.