Regarding IDEs: I don't use Emacs, but as I understand it, it isn't a bloated piece of software as a lot of people assume. It is actually a nicely integrated piece of software. Integration the way it was meant to, not integration like IE, WMP, and the OS.
And I find that once I got used to the CLI, it was definitely much faster for me than to use a graphical file manager to do my work.
As for a lack of documentation, it is a problem, but projects like
TLDP help. And as for the man pages, if you don't know what the command is, you're stuck...unless you use apropos, which is beautiful and useful for just this purpose.
So what I gather is that the tools are mature, but the users aren't used to them. Microsoft's newest stuff is considered better than the comparable stuff available for Linux (like MSVS vs KDevelop/Anjuta), but if you are able to handle your own projects, compilation, and debugging using make, gcc, and gdb, you're miles ahead.
Also, the market. You have Linux, made up of sys admins (not likely to be gamers), Gnu Zealots (not likely to play, much less pay for, a non-Free game), and others. Any gamers will likely have Windows for the purposes of gaming anyway, and with most games easily ported between Win32, Linux, and Mac, there isn't much incentive to use Linux more.
Seeing some of the posts on this board, I do hope that there are people who prefer to buy the Linux version of such games when they have the opportunity. I plan on buying the Linux versions of Gish and Bridge Constructor Set, as well as getting Doom 3 to run on my main system. UT2004 also has a Linux client and I do plan on getting that game as well. Half-Life 2 is a game I am not as interested in getting, but it is more because of a bad experience I had with Valve's "customer service". Still, the lack of a Linux client isn't helping their case.
I plan on developing games that work on Windows and Linux, with Mac ports on the way as well. I had BSD in the back of my mind, and I imagine it wouldn't be too hard to produce BSD ports. That would be a fourth platform to support (or would I have to support multiple BSDs? I need to do research) and opens up the market a bit, I am sure.