Ultimately, the answer is murky as the question: it depends. It’s up to composers to prioritize whose ears they care about, and much of that comes from one’s own values and personal experiences.
As someone who has studied both horn performance and composition, I find that I rank the importance of judgement, from highest to lowest:
If I’m not satisfied by my music, how do I expect anyone else to be?
If performers have to practice, rehearse, and present my music, shouldn't I consider their input meaningful?
When my composer colleagues face similar challenges in writing high-quality, shouldn't I trust them?
If an audience member takes the time to come to a performance of one of my pieces, shouldn't I inspire to make a piece worth his or her time?