You can only be a leader if you have followers. As mentioned above, the conductor is the only person involved in the performance who is not making a sound – the odd bit of grunting, heavy-breathing or singing along excepted! This creates an interesting relationship dynamic because whereas the ensemble can very possibly manage without you, the reverse is manifestly not the case!
Less experienced musicians need the conductor to teach them the music and make them play together, therefore there is a certain degree of authority by virtue of necessity. As the ensemble improves, so their reliance on the conductor in basic practical terms decreases. Professional orchestras can play almost any piece in the repertoire without the conductor. It might be a little scrappy in places, and it probably won’t be the most unanimous, coherent interpretation, but it will work. In this context, trust and respect are voluntary and the ensemble can choose to withhold them. If the conductor hasn’t been able to develop good relationships, he or she can easily end up not being in control of the performance. The concertmaster or leader can assume that role.
It is also very important to understand the complex hierarchy of relationships that can exist in ensembles of any kind or level. The concertmaster, leader, and section principals all have responsibility for certain aspects of how the ensemble functions and empowering those individuals can be hugely beneficial. As the conductor, we cannot solve everything so giving responsibility to others can only be positive. In a professional context, even if you are the chief conductor, you are probably only with the group for somewhere between a third and a half of their concerts. In that context, the concertmaster and section leaders may have more influence than you.