What is the significance of the “barn loft scene” in Fahrenheit 451, and why doesn't Montag eat the pear, apple, and glass of milk?

In this scene from part 3, Montag is fleeing the authorities by escaping from the city. Exhausted by his journey, he dreams of being in a hayloft and, at the bottom of the stair, finding a glass of milk, an apple, and a pear.
It is important to remember that these images are only a dream. Montag does not actually encounter any of these items while he is fleeing the city. In fact, these items represent the rest that Montag so strongly desires. This is not just a physical rest he takes because he is tired of running but an opportunity to sit and reflect on his life. This idea is supported by the following quote:

Some sign that the immense world would accept him and give him the long time needed to think all the things that must be thought.

What is really interesting about these items is that they are very simple. It is not a grand meal that Montag craves but just some fresh, simple food. This is perhaps a metaphor for the kind of society that Montag wants to be a part of: a society which lets people live a simple life without the constant pressure to be entertained, to drive fast, or to watch the parlor walls.