You can always tell the jacket designer is in trouble when the cover uses irrelevant type design to get the project over with.
But wait. Orwell sells at least a million copies a year.
It’s not the cover. It’s the book.
Sometimes a great cover can help a lousy book (for a little while).
And sometimes a lousy cover can kill a great book (like Turn of the Century by Kurt Andersen).
But for books, like most things, the stuff inside matters.