Article is overthinking and ignoring the probablle reality. Reacher's "line" may likely be exactly just that. A regularly used throw away that he gives so he can move on. Dixon likely knew him best, so had little to no expectations of Reacher failing to do Reacher things. Duffy likely had similar intuitive insights or her statement were actually face value honesty...either works for her as she gets the opportunity to control their ending and it works to the satisfaction of both of them.