I know this thread has been dead for a while, though it is nice to go over what everyone has said. I am currently on the audition circuit, and feel the same way as many other auditioners, though understanding the committee's stance is very helpful.
An earlier reply to this thread suggested that it is good that orchestras have multiple rounds to allow the potential candidate the opportunity to show off his/her stuff more than once. Obviously the first round must be impressive and give the committee something that they want to hear more. I think this is great. Although from my numbers, about 30% of auditions across the US don't hire, most still a least advance some players to hear more before not hiring them.
There was a recent audition that didn't hire for a concertmaster position. Understandably they didn't find find a candidate that fit their qualifications and standards. The shocker is that of the candidates (many already with considerable jobs and credentials), not a single one was advanced out of prelims. Nonetheless, the committee deliberated for more than an hour before reaching the conclusion that they didn't want to hear anyone again.
I understand that not hiring for a job is almost to be expected these days (seems so in vogue), but not advancing anyone seems pretentious and suggests alterior motives in the audition.
I would love to hear of other experiences of similar circumstance, and thoughts concerning the above practice. Thanks.

I have to wonder if it has become harder and harder to weed out the cans from the can nots. Within top schools, the average technical level of students is higher than the average professional level of playing from 70 years ago. Then add to this the sheer number of players who can play at top level today. With so much emphasis on technique, and with most players auditioning at the same level of competency, it becomes more difficult to agree upon that "something more" quality. How do you define something so subjective?

IMO, not hiring is not so much about being in vogue, but rather about finding a needle in a haystack. The haystack isn't filled with crappy players - the reverse is true, they are really fine technical players. They all have chops. Therefore, the needle has become thinner, smaller, much harder to define than 70, 50 or even 30 years ago.

With all the emphasis on technical perfection, is the process weeding out some of the candidates that the orchestra might really want? How important is musicianship and how and when is it assessed? If section playing is the most important why is it last? What are the pros and cons of exerpts first vs solos first as with most European orchestras?

Also, how many of the problems with not filling the positions is due to conflict or indecision in the committee? Is the committee composition the right one for the position? What preparation should the committee do before beginning the process?