What;s the deal with everyone encouraging others to change their light bulbs to the more efficient type.?

My question is, how many bulbs are they changing? Matt Damon said he changed all of his, but he lives in a mansion with 10 times as many bulbs as most people. He is also heating and cooling thousands of square feet more than the average home. If people want to promote conservation, shouldnt they lead by example and take things to their logical fruition: move into the smallest home your family can get by with. 1000 sq. feet should suffice for most "green" families and they would conserve a great deal more, right?