Apple has enough verticality in product, and such a large profit margin that they could afford the development at both ends of the connection.

While any one android developer doesn’t have enough volume to justify the NRE. They would need a standards body or cooperation to justify it. To get there they typically wait for Google to do the heavy lifting.

Samsung is perhaps the only one with the financial power but their making is much lower than apple’s.

I agree there’s no engineering barrier in principle.

They haven’t yet, probably because it’s hard for a number of reasons. Apple has an advantage in its silicon and software integration.

You are right, Apple holds an exclusive right to any novel RF or DSP techniques.

I would love to see the W2 chip available to third party makers such as JH Audio. I can't imagine Apple getting into the IEM market directly, but having the passive sound blocking of IEMs with the pairing quality of the W2, I'd be very happy.

I've got ears that don't really fit either the first gen or the AirPods Pro. Custom-molded IEMs would be great. With the detachable ear tips and looser fit of the AirPods Pro case, I'm hoping a third-party will come out with something similar to Etymotic's flanged ear tips.

W2 is actually used in Apple Watch.