I'd think that the OS is irreparably "blind" to devices connected to the 3.5mm jack, unable to identify them, and unable to discriminate among them, unable to s

I'd think that the OS is irreparably "blind" to devices connected to the 3.5mm jack, unable to identify them, and unable to discriminate among them, unable to send audio output to some of them, and not to others. A proprietary audio standard might include a way to identify devices (since manufacturers would likely have to use some kind of ID in the devices they make with Apple's blessing).