I think like seeing in UK, even for those on right, if you push things too far they can go over to other side. Its not like US where you can go as far right as you want and still win a large chunk of the population.
Smith and Truss are each a very particular type of ideologue with a base of and mandate from only party insiders and activists. American right-wing cranks at least have a wider base of primary voters from either open primaries or closed primaries with much lower barriers of entry before they're hoisted on a broader electorate.
If Paul Ryan had ever run for President, or taken over the helm after a Romney 2012 victory under strange circumstances, I'm sure we'd see something more similar happening here.