root access is also no longer true root access on a lot of linux distros that are immutable, and container-esque like interfaces such as namespaces + cgroups also limit roots power.
Pointless comparison as you the user still have full control over all of that on Linux.
Pointless comment as the same holds true for macOS. Yes, you can load unsigned kext still, and yes, you can modify the userland. Not as easily, but I would argue it is also not harder as on an immutable linux distro.