The Martian Chronicles Theme of Dreams, Hopes, and Plans

Even the worse humans have dreams, hopes, and plans. In The Martian Chronicles, every major character has some goal to increase his happiness (or avoid unhappiness): Yll in "Ylla" is trying to prevent his wife from leaving him; Captain Jonathan Williams wants to be celebrated for reaching Mars ("The Earth Men"); Benjamin Driscoll wants to plant trees to increase the oxygen of Mars ("The Green Morning"); and even the automated house of "There Will Come Soft Rains" wants to keep up its routine. Humanity is a race of dreamers, even when there are only a few of them left.

1. Not many characters in The Martian Chronicles succeed in reaching their dream. Driscoll manages to plant trees, and Spender's dream of a human-free Mars does kind of happen (though he's too dead to enjoy it). What is Bradbury trying to say by allowing so few characters to achieve their dreams? 
2. Which goals and dreams are presented as more worthwhile than others in the book? For instance, Stendahl wants to kill the censors—does Bradbury present that as a worthy goal? What about Parkhill's hot dog stand? Timothy's dad's plan for settling on Mars? Are all dreams equally valid?
3. Are there any major characters in this book with no goals or dreams? What about characters who want to stop something from happening? How do they go about stopping change?

In The Martian Chronicles, characters often fail to achieve their dreams because the world is constantly changing. A character may momentarily get his wish, but it doesn't last.

Although dreams can be hard to achieve, they are both achievable and necessary in The Martian Chronicles. A character without a dream cannot set a story in motion.