A: It’s all about licenses. The original book is in the public domain. The MGM movie is not. The original book had magic shoes, which were described as silver, I believe. It’s only the movie version which recast them as ruby slippers, no doubt to show off the exciting new COLOR film of the day, where silver would have been pretty bland by comparison.
We were not going to pay to license the movie rights from MGM when the book is in the public domain, and they’re similar enough that people can make their own connections. We dodged the illustration issue by making Magic Shoes an Action, which doesn’t have art.