I think this might help answer your question:
http://www.youtube.com/watch?v=LTdot_qjcts. IMO, Reasoner never really belonged on a nightly newscast; documentaries were his specialty. Had Frank Reynolds remained Howard K. Smith's partner on
ABC Evening News in the early 1970s, that network might have become competitive a lot sooner than it did--it took the return of Reynolds in 1978 to start ABC on its path to the number-one slot.