A mic element costs about thirty cents, and the processing power required for noise cancellation already exists in the CPU of the mobile device.
I think it's particularly interesting that Amazon has made microphe arrays particularly cheap, due to Alexa. MiniDSP offers a microphone array for under $100, which is an unheard of price considering what these cost ten years ago.
https://www.minidsp.com/products/usb-audio-interface/uma-8-m...