Reality is, hardware vendors want to maximize their profits and minimize expenses. Their expertises are in hardware and logistics, not in software. Why should they spend money differentiating software from a commonly established OS in a certain ecosystem if the whole purpose of the ecosystem for them is to leverage software and appropriate market leg created by other participants? Phone makers in China, producing cheap Android phones, are no different and work well in this way -- many of those even don't support Android Market and don't care about apps being installed but rather glide on the Android trademark.

In each ecosystem there are few players who are willing to differentiate on all scales, from hardware to software to services. But they are very few and they subsume most of costs on sustaining the ecosystem. If it pays them off, that is brilliant. But I wouldn't expect the whole configurability and extensibility story would sell well to all hardware vendors. A cheap way to ride on off others would sell the ecosystem more than anything else.

Sorry to be blunt.