BoJo, Rees-Mogg, and the rest of the ERG merry men behaved with complete impunity during the last year or so; they essentially operated as a party within the Conservative Party. Theresa May did nothing to stop them, largely because she thought, in the long run, she could sell her Brexit deal by proving that all of the alternatives were either worse or impossible. It didn’t work.
Today, the shoe is on the other foot, and Boris is threatening everyone who opposes him with excommunication. That will persuade anyone who has future ambitions. He only has a majority of one, however, and there are plenty of patriotic Tory grandees who will be willing to defy him. And so, the election is coming, as he undoubtedly knows.