I think it's business model. Because of the incentives (branding, revenue streams, etc.) an android handset maker makes its money when the phone is sold, and ceases to care. Because the phone is branded "Verizon" first, "Android" second, and "HTC" (say) third they don't care about the user once the phone is sold. Arguably, Verizon and Google should care more, but Verizon clearly doesn't and Google has too little influence. In essence it's a tragedy of the commons where the commons is Android (as a platform/brand).
Android was definitely written with multiple hardware configurations in mind. What I don't understand is why phone carriers and manufacturers simply provide the drivers for Google (and consumers) to work with. Essentially how one would install drivers on Windows. I don't understand the need for the drivers to be proprietary.
