It's the same axis: business-friendliness. The legal permissiveness described is critical for most software because it enables business adoption. But for a ker

It's the same axis: business-friendliness. The legal permissiveness described is critical for most software because it enables business adoption. But for a kernel, which sits at the intersection of hardware and software, "free as in beer" is not enough, there is another critical factor: how easy it is to make it work with proprietary hardware. A free kernel that won't work with my custom chip and whose maintainers won't accept the necessary patches to fix this state of things, is just useless to my business.