Of choirs and orchestras

There was a story the other day on our local public radio story that got me thinking about one of the key differences between choirs and orchestras: their relationship to the beat:

We revisit our conversation with classical choral composer Eric Whitacre, who has just been nominated for a Grammy for his latest CD “Light & Gold.” But he’s also known for his “virtual choirs.”
Here’s how it works: Singers around the world take video of themselves, upload them onto YouTube, and assembled into one performance. The most recent choir involved 2052 people performing Eric Whitacre’s “Sleep”.

As best I can figure from the video below, he conducts on the video, people record themselves singing to his conducting and upload the result, and he blends it all together in software.
I can’t imagine this working with an orchestra. But why not? I suspect the reasons are the same as the reasons choir conductors and orchestras tend to have trouble together; choirs and orchestras react very differently to conductors.

The most common complaint I’ve heard from choral conductors is that the orchestra isn’t with their beat, while orchestra musicians tend to feel that choral conductors are always slowing down to match their beat to what they’re hearing. I suspect all of these are symptoms of the fundamental problem, which is that choral singers follow the conductor while orchestra musicians follow each other following the conductor (this is also the reason why one of the highest compliments an orchestra musician can pay a conductor is that he/she “stays out of the way”: once a pulse is established, a conductor should simply let the musicians follow the pulse and not risk confusing the orchestra by also doing anything that looks like a pulse).
Choruses seem much more dependent on conductors than do orchestras, while at the same time less reliant on a standardized conducting “language.” Perhaps this is a function of the structural relationship between a chorus and its director being more like student and teacher than is the usual relationship between a professional orchestra and those standing in front of it, notwithstanding the “Maestro” honorific (which would probably choke most musicians if they didn’t subconsciously avoid the translation of the term).
Of course there was a YouTube orchestra. But it didn’t occur to anyone involved to use YouTube as anything other than a blingy version of the taped audition. It would have been a mess if they’d tried the Whitacre method, as well as much less profitable for all involved. Besides, doesn’t the joy of conducting fundamentally lie in wielding all that power in real time and seeing all those deferential young faces looking up in adoration?