I have noticed that Republicans seem to be rather self centered. Very rarely do they put cause ahead of personal ambition, unlike Democrats. See NJ 2002 and MO 2012 for two prime examples from each side.
I suppose what surprises me is not so much that Richardson is still running but that anyone is supporting him. Although, I suspect in reality, Richardson's support is not so much from people who think Poliquin is too liberal (as Richardson does) as from people frustrated by both major candidates.
And yet their frustration will create a self-fullfilling prophesy by ensuring perpetual disappointment. I am reminded of when I was listening to a radio program, the one that used to be on before Wild Bill Cuningham here in NC on Sundays, based out of Tennessee. Describing how Zach Wamp and another conservative were both running and that because neither refused to get out for the other, it ensured the nominated of what he termed to be a rino in Bill Haslaam. Of course I disagree with the assessment of Haslaam, but the example is the same.