Something like QNX would be a fantastic alternative to Linux, in my mind.

The problem, as I understand it, is that Broadcomm _refuses_ to supply a hardware manual for their SoC/peripherals...so nobody is willing to take on the challenge of developing a BSP for the Pi.

Linux wins by default.

Aside: One company did do a primative port, but here's their statement about it: "This is a very primitive BSP presently but capability can be expanded (to some degree) per user needs. Due to the lack of hardware manual from Broadcom, I heard no one wanted to develop QNX BSP for Raspberry Pi. Our Vietnamese engineer friends have gone through incredibly hard development without any hardware manual. They had to reverse engineer hardware spec from reference code. Now Broadcom and Avago merged we will see what happens to the documentation situation. "

The problem is most embedded devices don't run Linux. They typically run a per-soc (or even per-board) fork of Linux, often dependant on fixed versions of binary blobs loaded from userspace.

And that's assuming you can boot the damn thing without magic incantations and smearing lamb's blood on the correct pins of the SoC.

Perhaps the poster meant the numerous proprietary blobs and patches that can't be upstreamed for certain platforms.

The RasPi fixed those problems, though.

RasPi is not yet fully supported upstream.

But it's work in progress.

The RasPi still needs a GPU blob to boot right?

Yes, the equivalent of the BIOS on PCs.

Yep. I think the decision is Linux+Docker where all apps run in containers.

Sometimes people use a RTOS in the SoC. Some people run baremetal OS or NoOS in these SoC's. I myself and developing a baremetal OS for the Samsung S3C2440 and I find it hard to get documents from Samsung. I have to rely on the SBC manufacturer for the documents.