My three sons (6, 9, and 11) all take the "Santa" thing in stride. I think they've figured it out.
They also know that I do not earn a lot, therefore Christmas presents are not abundant. We live on a farm in Eastern Oregon. My children are raised with the encouragement to use their imagination at play. They are raised knowing there are those with FAR LESS to live on, let alone what they get for Christmas. They are constantly reminded by us parents that it is important to be giving & helpful any time of the year, not just on holidays.
In recent years, I've pretty well come to the conclusion that's what the Almighty expects us to put on our resume' before heading "upstairs."