All it takes is for Amazon to do a big marketing campaign and teach users that typing "horror.books" or "action.movies" to cause real problems to other retailer

All it takes is for Amazon to do a big marketing campaign and teach users that typing "horror.books" or "action.movies" to cause real problems to other retailers. People search google in google because they don't understand how the internet works, if an advert from Amazon explained how "action.movies" was a way to find action movies and "anything.movies" works too then you can guarantee behaviour will change.