A few years ago my children got a beautiful doll house made of natural wood, and I was so excited... I love natural wood toys, and this one was particularly well made. But after playing for a little while (like, two hours) they never went back to it again...
I was puzzled, and attributed to the fact that boys and miniature houses maybe are not a good fit... until my 6 year old son started his "house project." He was so excited he worked on it for days. He would wake up in the morning with all these ideas he wanted to incorporate into his project, and it has been so rewarding for him. He shows it to everyone that comes to our house, and he always says (with a very happy look): "It's all homemade".
I learned my lesson... at least for my kids, the capacity to transform common things into something else is deeply satisfying, and giving them the final product is not necessarily what will inspire them to create.