This is one of the few multi-page threads I read completely before responding, and I haven't sees once asked the following question : "who is the target audience of Linux?" I don't have the answer, I only have my answer, so all that follows is my personnal view.
There is none. The point of Linux is creating a great product. When someone wants to use it for something, he is welcome to modify it as seen fit; with the GPL safety that those changes will go public. This has happened on more than once occasion, however Linux on servers/supercomputers comes first to mind. The changes went back to the main branch, and independent devs got interested and contributed too. Now we're seeing the same in the embedded space : DMA-BUF was created to address a specific need for ARM vendors. In the end it was designed more generically than was originally needed, and the enablement of dual graphic solutions is AFAIK more of a side effect. Thanks to the GPL (again) the work went back into the main branch.
Now NVidia dances in, wants to hook in but oh surprise, it's an internal interface, and you can't link against it from non-GPL code. (Admittedly, this has never been tried in court, but who would want that?). Why is this? because when communicating with the kernel via system calls (exempted from the GPL derived work clause), the kernel can (and will) assure some type of security. With internal interfaces, this protection is irtually impossible. The best described case in the mailing list is a bug that appears somewhere, but traces back into the black box that is the blob, this creates impossible to debug issues, and for people hit by them, an impression that linux is unstable (and that no one is willing to look into their issues). In the end, they are making a decision which should be good for the product.
To the users (of which I am a subset), well, sorry guys, the qualty of the product should be and is the primary concern; jeopardizing this for a vendor (granted popular) that doesn't play nice doesn't seem like a fair tradeoff.
This was very personal analysis of the situation, and one more thing :
I bought my GPU, and I want(should be able to) to use it how I want. Imagine you bought a dishwasher into which you weren't legally allowed to use Calgon tablets, only had to use Sun tablets. The notion of "owner" is slowly fading, all we are is a "licenced user". I say NO! I own it, I use it how I see fit.
Third time repeated : my view only.
Agreed, the way things are becoming more tightly integrated, controlling them from dozens of different places (vendors) is unsustainable.
And i have to add my view, Linux will dominate in less than 2 years. If until the end of 2014, Linux is not the most used OS installed on all devices (including phones, tablets, googles), then I will not write again on any technology site.
And I'm still waiting an answer from AMD!!!