Even if Linux only has 1%, they have the top 1%. I don't know a developer or tech person that knows anything about how to work with windows that doesn't dual boot some flavor Linux.
The two things that are really measurable? Compare the number of books in book stores with anything of a computer / technology section and there are as many Linux only books as windows only books. The rest are cross platform with development books doing all their example work for a Linux machine / gcc.
Further, look at the Halloween documents. Microsoft is VERY aggressive about protecting its market share, and sees Linux as a huge threat where cheating and lies are their only defense. Admittedly DX10 is awesome, but the license fees to developers as well as Microsoft games, and OEM licensees come at a great discount if you are a Microsoft only developer / retailer.
Linux is everywhere and it dominates in the markets i has penetrated. The LAST place it has to touch is video editing (that is long off unless adobe ports premiere), and desktops. But so much of that is bulk purchases where the end user had no choice. Further, the teachers union has been a whore of Microsoft since Microsoft saw how successful Apple was with getting kids hooked early.
Another 'number' to check out. The profitable gamer right now on desktop computers are the MMO's. Look what what has stayed doing really well, and what good games completely tanked this year. Notice any pattern? The top games gave great Linux support.
While companies can have bad developers that can screw up any game, simply working from the ground up keeping in mind that your program needs cross platform support, it is EASY. You don't need to have two teams writing the whole thing from scratch separately. Windows is the dog in the cross platform battle. All you really need to do is use a cross compiler and debugger. It is not terribly difficult to write, compile, or debug / test for many platforms all on one machine, even without virtualization.
And finally, nothing gets tens of thousands of comments unless it is
Also, there are quite a few really great games for Linux.. they just end up in repositories, not game stores, or play in web browsers(not a fan myself, but sadly they "make the charts")
This isn't a call for games for Linux, cause they are there. It is a call for MORE games from certain companies we would like to see set free from under the thumb of Microsoft like so many others have had the chance to experience.