True. But when you look at this, isn't the deeper problem that Linux remains such a monolith, and there's a stark difference between "included" and "not included" in the kernel. It's now over 35 years old. The fact that we can't have stable APIs and develop more out-of-tree drivers is not a strength, it's a weakness.
Even old Unix systems like SVR4 managed to have stable, public driver interfaces, despite being rather proprietary. FreeBSD manages to have drivers in its ports tree, with a stable API for a given major version. What makes Linux so special that it can't manage this?
I understand all of the arguments about why this has to be so. But... they might have made sense in the early days, but after 35 years it screams of immaturity. Plenty of other systems, including other open source systems, manage to do this, including having versioned interfaces so things aren't set in stone. Linux remains right at the extreme end of guaranteeing nothing. I've long thought this was unnecessary and counterproductive.