Based on what I have seen, the turnover rate of musicians in a symphony orchestra is much slower than the turnover rate within software development organizations.
As a result, the consequences for a bad hire are extremely high. Many orchestras have the audition winner perform with the group for a probationary period of a season to help guard against this. That said, I read a lot on HN about the consequences of a bad hire for a an early team member, so although the timeframes are different, the fear is similar.
As you say, it's all about making the relevance of the process obvious to the candidate. Also, companies should be as accomodating as possible in terms of timing of appointments, etc.