Surely that leaves the door open for someone like Jeremy Hunt instead, since he re-imagined himself as the sensible one. And considering Johnson may soon be going, I don't think Starmer actually stands a chance if Hunt replaces Johnson.
Remember Hunt managed to upset all the teachers and all the doctors in his stints at education and health, and is the architect behind the highly successful local TV project. While he likes to portray himself as a steady pair of hands compared to Boris, he doesn't rate that highly with the general public compared to some of the current cabinet.
By pushing out all the moderate voices from the party, they've bet the house on the current lot staying popular enough to remain unchallenged. That's currently paying off for Boris, as if there was even one credible candidate in the higher tiers of the party he'd have been out the door months ago. But with the tide now turned against him, there's not much talent for the rest of the party to try and cling to.
Where Labour actually stand on most policies right now is pretty unclear. Some stuff they seem to back the Tories on unquestioningly, others they seem to disagree for the sake of disagreeing. Opposition means you don't have to have the answers, just the questions, but come election time that gets tricky. But at the moment it seems to be working - but not because they're now popular, but because Boris isn't.