The only difference between these "Trump campaign on verge of collapse" stories now and the several "Trump campaign on verge of verge of collapse" stories we saw during the primary is they aren't intersperse with episodes of Trump crushing his competitors at the polls.
How many times have we been told by CNN that Trump had crossed some sort of line and Reince Priebus and the GOP Brahmins were going to do... something.. to put a stop to it all. Remember how aghast they all were that Trump said a bad thing about John McCain? That was going to end everything way back when. Turned out voters didn't give a shit.
But voters don't have any input to offer now until November. So "the narrative" is out of their hands. Doesn't make what we're hearing any more true than it was before, though.