QNX is 30+ years old, and is effectively defunct except in a few niche markets after being acquired by Blackberry (and was losing market share to Linux for decades before that). QNX is not an example of a new and successful proprietary kernel competitor to Linux, despite being well-regarded and pretty neat technology.

It was. And it's heavily on the decline, since it's substituted for Linux in a lot of new projects. This underlines SwellJoes assumptions that new operating systems have it very hard.

And is about 35 years old... GP mentioned 'last decade'