Dude, the movie was building up from the get-go that this was a story about Jyn finding herself and completing her father's work. The emphasis of the movie wasn't about getting revenge, ergo, wasn't building toward a confrontation between the two. Krennic wasn't out constantly looking for Jyn; Jyn was not constantly looking for Krennic. The movie had a lot of events involved with the two, yes, but their dislike or hate or whatever for each other wasn't compelling Event A to move to Event B in so on. It was not building to this ultimate, confrontation. Krennic just, basically, happened to run into Erso on the tower.