> Someone must answer questions such as these if a performance is not to sound indecisive or chaotic, and it is far easier for one person to do so than for 100 people to vote on each decision.
It strikes me that this is a bit akin to the role of a good CEO, or an active monarch in a democratic monarchy: not to direct, but to roll with the flow, and influence things just a bit — like a harmonic knocker, giving just the right impulse at just the right moment.
Except in rehearsal the conductor has imposed his vision of how things will flow in later performances. Different versions of the same piece from different conductors can sound extremely different, although the sheet music is the same - different tempos, different changes in tempo, different dynamics, phrasing, relative volume of instruments, timbre (quality of sound), different lengths of notes and accents and attack on notes, etc etc, and each composer has their own idiosyncratic ideas and preferences, both about what the composer wanted and what they want the piece to sound like. Sometimes different numbers of players are used. Also the particular way the conductor speaks to the orchestra about the music and the players, and other things, what they say and how they say it, can have a huge effect.
"To influence things a bit" is nothing like it. A performance may give that impression, but the nature of the performance in all those details and more has been thought out by the conductor and rehearsed beforehand. The orchestra has been taught and trained in exactly how the conductor likes it, and that's what you hear.
It strikes me that this is a bit akin to the role of a good CEO, or an active monarch in a democratic monarchy: not to direct, but to roll with the flow, and influence things just a bit — like a harmonic knocker, giving just the right impulse at just the right moment.