The only thing that will finish Johnson is senior Tories and the right wing press deciding it's time for him to go, and even then it'll just be to facilitate a quick change at the top before normal service resumes (i.e. the Tories back to 40%).
If you're pinning your hopes on a grand unmasking moment with the boomers, that translates to actual changes in voting behaviour, you're in for a long wait.