Things can also change. It's strange that people struggle with that concept.
Generally speaking if a politician who was popular because they were seen as 'not a politician really' acquires a reputation as not only 'absolutely a politician, actually' but a backstabbing careerist scumbag to boot, they do not regain their former popularity.
Indeed. Johnson's appeal to the constituencies that won him the London Mayoralty in 2008/12 died with the referendum. Since then he's lost all credibility by parroting Leave nonsense talking points about 'no deal' and 'alternative arrangements'. He's also left himself wide open to criticism from the Farage side of things by voting for May's Withdrawal Agreement, despite having denounced it for months beforehand.
Sure, Johnson has a retail politician's charisma and a hardcore fanbase, but to be frank, he's yesterday's man. Corbyn may stumble for other reasons, but the obstacle to him becoming Prime Minister in a few months is not Boris Johnson's popularity.
