#4 makes me laugh because I had that thought when I was trying to work with bluetooth. I think the real problem is two-fold. The original spec required approval from all members of the consortium. I think a lot of things were left out that are really important, such as security. I know they had security from the start, but really, it's bullshit. Plus the original chipsets were incredibly expensive, and my pure speculative thought is that they cut corners (the firmware part) to bring them out to market. I was really surprised, shouldn't have been with hindsight, to see when bluetooth chipsets started to reach price parity with wifi chipsets.
The second thing is that much of the low level firmware for the stack is closed source stuff that is written in house. I suspect, after working with some of that shit, that it's poorly done and is a major cause of unreliability. Don't know if it would make any difference if it was open sourced, because the hardware/software combo is a lot like what you see with graphics cards. Everyone has their own secret sauce and they don't want to show it to the world.
The second thing is that much of the low level firmware for the stack is closed source stuff that is written in house. I suspect, after working with some of that shit, that it's poorly done and is a major cause of unreliability. Don't know if it would make any difference if it was open sourced, because the hardware/software combo is a lot like what you see with graphics cards. Everyone has their own secret sauce and they don't want to show it to the world.