It's been a few versions since I paid close attention, but as I remember OS X ships with only the bare POSIX tools, plus a few extras from the FreeBSD userspace. It lacks stuff like perl, python, curl, wget, ssh (maybe: not sure about that one), tcpdump, etc... That's all stuff the poor user is going to have to figure out how to get.

And as mentioned, the existing package systems for OSS software are really primitive. There's just no equivalent for, say, the Ubuntu synaptic tool for new users.

I'm not trying to make this into a flame war: clearly you can achieve a pretty solid command line experience in OS X if you know what you're doing. But you're never going to learn it there without a bunch of headaches if you don't already have that expertise.