It does seem odd that so far at least Duncan Hunter hasn't gained more traction.
DH is a good guy, and a good conservative, but at this late date if he hasn’t gone anywhere he isn’t going anywhere. He’s been on the political scene for a long time. During all that time, what statewide races has he won?
Whatever the reason for his lack of traction, now and in the past, it’s irrelevant at this juncture.
DH has no traction because he has no traction, and all the wishing and hoping in the world is not going to change that fact before the primaries begin.