Right, that's a problem. I fully agree with you on that. I just think it's important that fight for the right thing. Secure Boot isn't the problem. In fact, most people probably should leave it on because it's a good security feature. It is absolutely critical that these features work for users and not against them though.
Funny you should mention Microsoft Windows. As I understand it, the phone OS is now unified with tablet and desktop - but you still can't run anything but windows on a windows phone. I don't expect them to offer up the driver source code (all though that would be nice) - but an open boot loader would be a start.
I suppose it's no surprise. It goes something like this: a) underwrite the device (not necessarily lose money on every sale, just lower the margins), b) introduce an app store, c) take a cut of every transaction.
As long as users and developers need your OS, your device - your appstore - you will make money.
Secure Boot is the best example for that:
• On Windows RT devices it always was mandatory and could not be disabled.
• On Windows 8 devices, manufacturers must give users an option to disable it.
• On Windows 10 devices, it is now in the manufacturer discretion whether it can be disabled or not.
The next step is obvious.