I was not referring to the Echo as a complete device (which is certainly not competitive with Roger in its intended or practical function), but specifically to the ring of beamforming microphones it uses to locate and pick up users interacting with it, in noise and at significant distance. By now, this type of microphone array is neither “unobtanium” (so to speak) nor only the preserve of FAANG-level tech behemoths, and indeed component suppliers like Analog Devices will explain to anyone interested in implementing this type of solution how to do it because they’re happy to sell the parts for literally pennies:
https://www.eeweb.com/microphone-array-beamforming-tutorial/
Obviously the secret sauce is the software, and the question of what’s “fair” to pay for that is a different issue than how much more a device costs than its bill of materials. But if there were an open interconnection protocol (with a lighter-weight power draw than Bluetooth) I believe 3rd party devices could hit a very desirable price-performance compromise between the two levels of PartnerMic and Roger Select.
Can I call up an EE design house in Shenzhen, and specify an STM32-based, LiPo-battery equipped, beamforming Bluetooth remote mic with reasonable near-field fidelity? Yes. Will it cost more for industrial design to make the enclosure look nice? Absolutely. Can I have them made for less than $300 in quantity? Possibly, with a major caveat around the definition of “quantity”. As an experimenter, I wouldn’t be worried about working on a homebrew BT solution but I have no doubt that patents are what is keeping other players out of this (small, but still competitive) market.