Yes, that argument was suggested by Reuven Frank, the legendary producer of the Huntley-Brinkley Report and later the head of NBC News. He wrote about it in his memoir, Out of Thin Air: The Brief Wonderful Life of Network News:
"Long after the AFTRA strike, too late to ask for a survey or an opinion poll to check it, I came to believe that Huntley working those two weeks of the strike and Brinkley not working eroded their audience. [...] No one said so and it may not have been true, but it appeared that Brinkley disagreed with Huntley, that there was a rift. [...] if some perception of friendship or at least cordiality between Huntley and Brinkley swelled audiences, then it is conceivable the public was put off by what it saw during the strike. If people had been attracted to these two men because they seemed to be friends, it made them uncomfortable when that was disturbed, like children when their parents argue. It is not that people chose sides, but what had attracted them had been withdrawn. I do not know that this is what happened; I do know that in television that is all it takes."