I'm a happily married husband and father. Happiness is a choice. This kind of desperate critique is not based on observation alone but subjective interpretation, and not one of good faith. Poots and Eisenberg deliver on the acting, but their characters are unrealistically unstable, especially Jesse's.
It's like this - if you want a happy life with someone who wants a happy life with you, the two of you will have it. This couple was written to behave irrationally. With no way out, a rational person would settle in and view the experience like a vacation. Even many of the men and women in the Nazi death camps learned to joke about their circumstances. The protagonists are so unlikable and unrealistically hopeless. They barely attempted to use the boy to learn more about their circumstances.
Whatever vague point the creators wanted to share about life, whatever meaning was supposed to be conveyed, it was not. The story was a poor vessel for any but a nauseating feeling at the end when you realize there's no lesson to be taken from all this helplessness and confusion.