I knew that, but you are wrong about the "none" part. Shania Twain actually does write her songs, which actually is her greater talent. Gretchen writes as well.
My point about "Before He Cheats" wasn't a compliment ab Carrie but rather whomever it was who did. I have no problem with pairing a talented singer who can't write with a talented writer who can't sing. It's win/win. Why should it matter?
Exactly. Frank Sinatra's list of songwriting credits is rather short. ;)