The Ones Who Walk Away from Omelas

In The Ones Who Walk Away from Omelas, it describes festivals and complete bliss. The narrator says that it's almost impossible to describe the town and do it justice. Does this happiness come at a cost? In the basement or cellar of one of the pricate homes, there is a room that is locked with no windows. Inside this tiny, 2x3 room are mops, a rusty bucket, and a child. Helpless, tiny, thin, under developed child. The story  talks of how discusting and frightened the child is, yet no one helps. The narrator say the happiness of the city depends on this child. Though what would happen if they let him/her out? Would there happiness disappear? There would be dispair and disaster taking over the city? I don't believe they know exactly, because they haven't tried to let him/her out. Maybe it got started by a mother or father abusing a child long ago and they justify it by making up a myth that if a child is let out of there the whole city will no longer be a happy, festive place.
They are not even allowed to speak to the child, so after many years they can't talk and only speaks jibberish. Also, it can't be the same child all the time. If a 50 years were to go by, if the child were to live that long due to little nutrition, and they die, do they replace the child? Then what would the process be of picking the child? It could be like The Lottery. Then it also talks of those who cry about it to others, but they can't do anything because they believe there's no hope for the child even if they let them out. Also, there are those who leave after seeing him or her. They leave alone and I believe it's because they feel guilt and don't want to be a part of a town that harms a child in that way. Though, if the harm of one saves hundreds of others from hurt would it be worht it? No, becuase no matter what you can't be happy all the time, and if you are you don't feel much or anything if you dont feel sad for the person keeping you from pain.