[UVB-76]

I'm no sound engineer, but intuitively the design of the AirPods slightly exacerbates noise cancellation issues by:

a) Placing the microphone further from a person's mouth, or at least, removing the option for people to hold a wired microphone close to their mouth;

b) Significantly reducing the distance between microphone and speaker.

[mikeash]

I never see people wearing headsets that place the microphone near the mouth outside of specialized settings, nor do I see people holding the microphone to their mouth. I suspect they generally want to keep their hands free.

I don't think the distance between the speaker and microphone matters. Canceling out the noise you're emitting isn't hard with modern signal processing.