The idea that the best possible title for a question will also be a question is, in short, completely off-the-mark. Titles are titles and have their own grammar.
Also, while you can no longer earn many points writing questions on Stack Overflow (new point system + tendency to not upvote questions), the best answers come to questions that have interesting titles/many upvotes/pageviews. Good titles entice the best answerers to read the question.
