Apparently, up until the beginning of the 20th century, people had no idea what the shape of their country was. As an example— the ultra-jingoistic book Le Tour de la France par deux enfants (1877), which narrates the travels through France of two young boys, had the aim of instilling a sense of French grandeur and unity in its readers; yet it didn't even feature a map of France. The map only came with the 1905 edition of the book.
Now we all know how prominently maps feature in RPG supplements. Even though supplements describing a given locale are normally restricted to the GM's eyes, it is a fact that players often have access to them— and to their maps. As a result, players have a good sense of the geography of the GM's world, or at least of the part where their adventures take place. I for one am a maps buff, and I love supplements such as Sartar: Kingdom of Heroes with its beautiful, full-colour maps. Heck, even the 14-page Player's Primer has a nice map of Sartar on p.5. Now I'm not suggesting these maps be removed, but how can you give the players a sense of wonder at the size of the Lunar Empire or at the complexity of the navigation in the Rightarm Islands if they know the geography?