If every contract already contains an implied duty of good faith and fair dealing, isn’t it already part of American contract law?

Individual Research Paper
Topic Selection and Topic Statement

Original thesis statement: Every contract contains an implied duty of good faith and fair dealing and should become part of the U.S. contract law.

Argue: If every contract already contains an implied duty of good faith and fair dealing, isn’t it already part of American contract law?

Answer the question and revise the original topic statement to reflect an answer to the arguing question.