The American dream is not a thing in physical terms but an idea that lives or dies with certain beliefs in society. Can it die? Yes it can if those beliefs are purged from the conscience of society. This is what Jefferson meant by watering the tree of liberty with the blood of patriots from time to time.
Many people bemoan the loss of the high paying jobs and the mansions and swimming pools we all want to have. They look around them and see their dreams of easy living collapsing and the debt piling up about to drown them. They see life becoming harder every day and society becoming more dangerous.
The American dream is not about houses, swimming pools, expensive vacations or fancy cars. These are all benefits of that dream. They are the icing on the cake, not the cake itself. The American dream is about the freedom to earn those things if you are smart enough and work hard enough.
The American dream is about freedom. The ability to live the way you desire and to be all you can be in society. It is the freedom to build and accumulate and make something of yourself. It is the freedom to go from rags to riches in one generation because of your will and abilities. It is the freedom to own your own property and use it to better your position in society.
The American dream is about the freedom to walk into a clearing with a hoe and shovel and build a farm. It is about the freedom to walk into a stand of timber with nothing but an axe and an idea and build a town. It is about the freedom to design a new machine from your imagination and build a factory to use it.
For the dream to die freedom must also die. As long as you have the freedom to do your best the dream is always possible. The slow loss of personal freedom over the past century has led to the diminishing of the possible. We no longer see the possibilities because that ability is being taken away from us. Tyranny is the lack of possibilities forced on the population. You can no longer be all you can be because you are constrained by others that want to limit those possibilities.
When your freedom is constrained by those that are willing to use force to limit those possibilities, you must defend that freedom with force to preserve it. That is when the tree of liberty gets watered. That is when the dream is reborn to flourish once again.
The American dream can die but only when we fail to water it and let it die. If Americans want to eat cake then they first must bake it. Only then will they be able to treat themselves to the icing on it that we all love so much.