> you can't have root access without unlocked bootloader, simple as that
Various EoP exploits for the kernel begs to differ. That said, even though your statement is broadly true, conflating unlocked bootloader and root access in the OS under an umbrella term of "root" is still sloppy terminology. The terms are related, but don't mean the same thing. For instance, many x86 PCs essentially have locked bootloaders by default (secure boot), but you can still get root access on them because the operating system explicitly allows it.
Various EoP exploits for the kernel begs to differ. That said, even though your statement is broadly true, conflating unlocked bootloader and root access in the OS under an umbrella term of "root" is still sloppy terminology. The terms are related, but don't mean the same thing. For instance, many x86 PCs essentially have locked bootloaders by default (secure boot), but you can still get root access on them because the operating system explicitly allows it.