I read it as, "[Practically speaking,] [f]or anything to change...Congress must act."

You are right that Congress is not the only branch of government that is constitutionally permitted to opine on the scope and subject matter of patents. But, as you note, the Supreme Court has punted on this, which indicates that they prefer to let change come from the electorally responsive branch. Which makes it likely that this decision will be reversed or remanded.