She has observed countless instances where Harry's petulance and stubbornness have won the day, causing those who are less confident, easily intimidated, or in awe of his royal status to give in.
This includes his old school pals, former Army colleagues, friends of the family, people he grew up around, and mere observers like herself. Even members of his own family have been exasperated by his destructive and self-destructive behavior.
Individuals, both old and young, who have tried to talk some sense into him and save him from himself appear to have been systematically shut out of his life as if punished for contradicting his increasingly toxic and paranoid narrative.
However, this behavior has not done him any favors, as he finds himself up a creek without a paddle. The Coronation showed that Harry is not a meaningful part of the Royal Family's future.