I think the point is that even drivers could be non-trusted and live outside of the kernel and just provide the exact service required with minimal access.

That said, why do we still need drivers in 2025? Most regular printers should be dumb, U-MASS should be dumb, webcams should be dumb, monitors are dumb, etc... very few devices coming really needs custom drivers anymore (even with many customizations we could provide class specific descriptors that drivers could adhere to).