Also, why not make it so that they can be used passively? What's the downside?
If by passively you mean plugged into a headphone port, the answer is that they can’t because they need power. Their big selling point is supposed to be computational audio. That obviously doesn’t work without the compute part, which in turn requires power.
I’m sure the product team at Apple considered that use case, and it didn’t make sense to include it in this version due to time/weight/cost/complexity constraints.
If by passively you mean plugged into a headphone port, the answer is that they can’t because they need power. Their big selling point is supposed to be computational audio. That obviously doesn’t work without the compute part, which in turn requires power.