You're taking about how things are, the comment you're replying to is talking about how things could be. There's not a contradiction there.
Originally, x86 processors had 4 levels of hardware protection, from ring 0 up to ring 3 (if I remember right). The idea was indeed that non-OS drivers could operate at the intermediate levels. But no one used them and they're effectively abandoned now. (There's "level -1" now for hypervisors and maybe other stuff but that's besides the point.)
Whether those x86 were really suitable or not is not exactly important. The point is, it's possible to imagine a world where device drivers could have less than 100% permissions.
Originally, x86 processors had 4 levels of hardware protection, from ring 0 up to ring 3 (if I remember right). The idea was indeed that non-OS drivers could operate at the intermediate levels. But no one used them and they're effectively abandoned now. (There's "level -1" now for hypervisors and maybe other stuff but that's besides the point.)
Whether those x86 were really suitable or not is not exactly important. The point is, it's possible to imagine a world where device drivers could have less than 100% permissions.