When the kids don't want bigger and better house

I have been thinking about whether I should buy a new, bigger house, or not. I discussed the possibility with Adrianna and Adora. I initially imagined that they would jump up and down and applaud the decision to have a bigger and better house. To my surprise, or perhaps to some extent not to my surprise, they did not want to have a bigger and better house--in fact, they wanted a cozy, small house. The house we are living in currently is extremely spacious. I am very proud of my children for their conscientious effort to conserve and live a simpler life.When my children are so proactive in conserving natural resources by wanting less luxurious living environment even when it's provided to them, what should we do as parents?