In theory, I agree with you. In practice, however, they've lost elections before, and it's never really affected their policies. They move ever more right, regardless of what happens. The border wall used to be bad, and now it's something they actively pursue. Universal health care used to be a thing they'd at least mention (and it's still a very popular position to take), and these days? Not a peep.

Their strategy, at least the past three cycles, has been "I offer you nothing, but do you really want to vote for the other side?" And I don't see that changing.