Technically there is a workable solution somewhere close to what you describe, and it should cost tiny extra power usage vs the fully centralized design. But i

Technically there is a workable solution somewhere close to what you describe, and it should cost tiny extra power usage vs the fully centralized design. But imagine you are a company running one of the big mobile platforms. You could invest effort in the APIs and OS behavior to do this, and the payoff would be loosening your grip on the ecosystem. Tough to justify to those watching the ROI.