Because printing is not part of the base system but instead is supported by extensions.
Yes, I modprobe lp in my /opt/bootlocal.sh on the one computer that I have that still has a parallel port.
FYI In the base is a tiny script that I use for cupsless, spoolerless, direct printing of text files, i.e,. my programs and scripts, it might be useful to some
text2lp0
Of course, it only prints plain text directly to lp0