It was not a definitive comment, just about his failure to grasp the import of Brexit. Your comment is closer to the all encompassing summary. He was not completely useless: as Mayor of London he realised his chance and screwed billions out of the treasury for that city on transport and other projects. I blame the treasury for doing something that was to the detriment of the rest of us.
He was typical of his type: rich, well educated and connected he thought he was ‘owed’ the office of PM. Cameron was another like that. Arrogant arses, basically.