The idea has been around for quite some time. But it is always dropped.
My guess is that, assuming the most basic and absolute physicial design, the light would flash for silly things like booting, upgrading firmware, checking health or stuff like that.
Flashing is easily fixed with a capacitor and also not a bad thing if it turns off when it loses power immediately. The only explanation that makes sense to me is it being separately controlled is a feature not a bug.
I agree on the capacitor fix for flashing, I pointed it out in another post.
In this case I was referring to false positives to the user.
This would mean we can't update the firmware without causing the user some paranoia.
Also. Would an app requesting permission to use camera itself send some power to the camera to verify it is available? In a similar vein, what about checking if the camera is available before even showing the user the button to use the camera?
Maybe there's solutions to this, I'm just pointing out some reasons they may have gone the software route instead of the hardware route.