Abbott was an idiot. He eventually did one too many stupid things to be allowed to continue.
His support of Bronnie was way too far for most of his colleagues and for many the final straw. It was a disaster for the govt. she should have been told to resign or sacked day 1. what she did was egregious and very close to fraudulent and they all knew it. The griping about his support by Liberal senior to junior, esp senior, was epic and in the end brutal. It was over then, he was a dead man walking.
add that to Knighthoods, then knighting Phil the Greek. Medicare, Maternity Leave blah blah blah.
Previous PMs, Howard, Hawke, Keating, Fraser etc had some idea. Tone didn't give the impression he had even the faintest idea. either in policy or dealing with his party room.
The ABC had little to do with his demise V Jet, he was incompetent and damaging to his own party. any and all really damaging stuff was coming internally from his own side to help get rid of him.