I read the same books every night. And every nap. So I've already got "I Can Fly" memorized. The illustrations are sooo fantastic. I am already being trained to be a huge Mary Blair fan.
You could say that when illustrators, designers and artists copy the mid-century style of artists like Mary Blair, that they are stuck in a rut. But is it really a "retro" style? I think that a style like this will exist in any era, as long as there are people around with a childlike sense for imagination and simple forms. It just feels natural to me!