There are a good many different flavors of *nix available. "Unix" is not even a totally descriptive term because there is more than one flavor and that includes Linux, among many others.
Unfortunately many Mac users don't understand that many *nix users have no more fondness for Apple, with or without OSX, than they have for Windoze.
Many commercial developers, especially those with existing *nix products which can be readily modified to run under OS X, most definitely have an interest. But if you visit sites like Slashdot you'll discover that many Linux users dislike Macs more than Windoze. It varies. Usually Windoze draws more boos.
There are dozens of different distributions of Linux alone. Linux users can't agree among themselfs. The FreeBSD people and the GNU people don't agree. The GNUStep people don't agree with the NeXTStep people (Apple bought NeXT, the basis for OS X). Many GNUStep people are former NeXTStep people who don't like OS X.
All is not bad in the world. In fact a review of the daily posts of updates and new files on Version Tracker will show there's a flood of OSX freeware and shareware, much of it derived from Linux, FreeBSD or whatever, or written, new, for Mac OS X.
Most Mac users live in our own little world too much and repeat all the same nasty things over and over about Windoze users who represent something like 90% of the desktop users. Mac users amount to (depends on who you read) about 5% and the same is roughly true of "all other," mostly *nix people.
Reading a thread at SlashDot (probably the main watering hole on the net for Linux types) when OS X is brought up will quickly show you that very little is even known or draws any interest from the average Linux user. But Apple has something that Linux doesn't have and that's the OS X GUI. Linux (vs. + other *nix brands & flavors) have been struggling for years through the open source, volunteer programmer process to write a decent GUI.
A Graphical User Interface is what OS X largely amounts to dropped on top of a (variation) of the Darwin kernal which is derived from FreeBSD. The various forms of a GUI for Linux have progressed, but it's questionable there will ever be anything equivalent to the Mac GUI or Windoze.
But Linux and Mac users share one clear and common concern. Both are in distinct minorities. Linux users have their "free" open source software to use on whatever PC they choose to buy. They don't have the reliance that Mac users have on applications software that is written to specifically work with the Mac GUI, i.e., Microsoft Office, Photoshop, etc. (we all know the litany), but the fact remains that we are in a minority, can use all the help in terms of *nix software modified to run under OS X, and have already begun to "grow" our own culture of *nix geeks, those Mac users who have been running Linux servers for years, and now have the best of both worlds with Mac OS X.
But we do share a common interest and common concerns, mainly one: Micro$loth.
