You have to understand how Vance views the issue. For him abortion isn't a meet in the middle stance. Abortion to him and folks similar see the matter as only having one possibly correct solution.
Thus for him, "Americans instinctively mistrust us" doesn't mean that his position would evolve, it's that "to him", he's done a "bad job" making your stance evolve.
The hard line Republicans aren't interested in finding common ground, they're more interested in what you will change your opinion to or at the very least what unacceptable positions you'll tolerate. There is never going to be an evolution or common ground to be found with these folks because that's distinctly not the position that they are looking for.