> I have no doubt at all that if you could get a few thousand of those arm chips in the hands of promising young programmers WITHOUT the fancy GPU to fall back on, one of them would shock you all by making it do things you think are impossible. But if he's told instead he has to use the high level interface and pass OpenGL to a blob he cannot inspect or modify, he'll probably just pass messages until he gets bored, or finds a bug he cant fix, and then move onto something less frustrating than proprietary computing, like playing football with a bunch of guys twice his size or having molars extracted for fun.
nobody is disputing that more access would be better, but you are making the assumption that doing new and interesting things with the video is the primary purpose of all users of the device.
It may surprise you that most people who use computers aren't going to try and debug video drivers or firmware, even where they do have that capability. They will usually just download the latest version to see if it's fixed, live with the problem, or revert to a prior version.
We saw this with the Intel video drivers a few years ago, fully open-source drivers, but when there were problems in the drivers in a ubuntu release, 99.999+% of the people just stuck with an older version.
For those people, the difference between a high-level API and a low-level API is meaningless. To be fair, probably 90% of them wouldn't care if the entire driver was a binary blob, but that still leaves a very large group of people who benefit from having all the kernel and userspace stuff being open, even while the firmware is closed and has a high-level API