It’s the kernel. For starters, Linux is a kernel. I don’t understand your point, the people running the Linux ecosystem (the corpos injecting money in the infrastructure and participating in the governance through the Linux Foundation) don’t care about user ownership. NVIDIA is a bad collaborator but it’s still allowed to do the shit they do. As other nonfree contributors on drivers.

But let’s suppose an open and universal implementation standard of ARM and modem drivers was enforced? We’d have hundreds of viable Linux phones already. The battle wouldn’t be pretty but the alternative would be the current shitty state of affairs.