He didn’t move against Johnson but neither has he been seen to be too associated with him. Few people had heard of him before February. He doesn’t seem to have any enemies in the party.
Tories are obsessed with Churchill and he can pull off the Churchill thing pretty well. Johnson couldn’t because he was a cad and a bounder who couldn’t keep his mouth shut. Wallace is seen to be the opposite. A quiet, determined Army man, a safe pair of hands.
He was a Remainer but his relative quietness and his being seen to be morally clear and vocally pro-Ukraine will override that.
He wouldn’t have had a hope of being the next leader only for Russia inflicting war on Ukraine, but events change careers.
When the history books are written about Johnson’s reign I’d say they will make some reading. Even though we don’t know the half of it I’d say he is the worst, most unprincipled and self serving person ever to hold high office in the UK. It will be interesting to see in time what damage he has done to the country.