How many of the drivers installed to [BootDrive]:\OS2\BOOT do you use? Most of us only use a few but the installer puts every driver that may be needed. Is that just in case we change hardware configuration in the future?
Just trying to draw a comparison with cups...
Maybe 10 to 20 % of them. But this directory contains only 3 or 4 megabytes to draw a comparsion. Usually I delete not necessary device drivers for microchannel systems by a small REXX procedure after a finished installation.
You could possibly go through the cups installation and remove unneeded files eg man pages but be careful you do not remove something you later need.
There is a man reader somewhere, possibly hobbes, but the online docs do the same job.
A large part of documentation is only useful for developers or administrators. I doubt that average and users are able to install and use man page viewers under OS/2. Of course there's cawf as a small solution for command line paging, but it has some limitations. I never complained about man pages with XFree86/2 but there it was working almost out of the box by xman. Even the developers doing the port seem to hate man pages, otherwise they would convert them automatically to INF-files at time of the build.
Does cups need tcpip to print locally?
I don't think so but it is a long time since I last had a local printer I may be wrong.
All included executables and DLL is dynamically linked against TCPIP32.DLL. It becomes much worse for printers connected through serial and parallel ports. Then you have to run additionally a local LP daemon.
You may need a [BootDrive]:\tcip\bin directory to put the cupslpr.exe file into but there is nothing stopping a user from creating that directory on a non-tcpip-installed system and adding it to the config.sys PATH.
OTOH: you could probably install this file to another directory in the config.sys PATH - I am not sure if it is "hard coded" to BootDrive]:\tcip\bin.
Of course paths are hardcoded. But I'm aware of it. But documentation is not very friendly to end users in this area.
Of course, if you do not have tcpip installed you probably do not have a browser installed which means no using the cups browser interface to setup and test your printer. That means playing "command line cowboy" with all those commands that I have forgotten...
Because CUPSD also includes an integrated web server etc. it's not possible at all. But again, probaly nobody tested the command line tools. The included localization files (which use GNU gettext?) are in UTF-8, so it looks like garbage on non-english systems and causes additional headache.
A Mac that does not use cups... Must be Ye Olde Apple Mac :-) pre-PC hardware and pre-linux?
It's a PowerMac G4, one of last ones that are able to run native MacOS 9. Ok, I could also use Snow Leopard which still included Rosetta emulation on newer devices. But that's too much effort for just running FreeHand and Acrobat.
Out of interest how old is the hardware running OS/2? I ask because it sounds like you may have disk space limitations in these days of Tb sized drives.
They were mostly control devices at ages from 0 to 15 years. I don't know any reliable backup and restore solution for stand-alone systems that could handle Tb sizes nowadays under OS/2. So some of the devices only contain only CF cards that have to contain everything and were connected to process printers or barcode devices. Not everybody wants to pay extra money for connected industrial ethernet stuff.
For development and administration workstations it's not a big problem to have more storage space for printing system (than for the base OS itself) available. But on production systems it will increase (doubles) downtimes for creating backups of a system partition.
To make it clear, here is no hostility against people who tried to make CUPS working under OS/2. But to make it ready for an end user it's a long way to go.