This is the disillusionment of the entrepreneur. There is no such thing as success. It is a moving target. A mirage. By the time you attain what you thought was your wildest dream, reality has moved on and left your dreams in the dust. And the desire for success grows stronger still.
Can we ever be satisfied with our current circumstances? I would say no, and we should not be. Otherwise we would probably still be in the stone age. So should we aim for success? Yes, but we do not let our goals consume us. We must have goals to ensure we do not stagnate, but we should not be too obsessed with reaching the goal, to the extent that all we think about is the end result (success). The journey is much more important than the end, like they always say.