sure it is a large number, but large != most.
every programmer i know works in a windows dominated environment. this is a small sample though.
i believe that in back-end only environments linux has some serious popularity but i can't comment on how many studios use it as their development platform because i have no great experience there (actually i work in office where they develop such things, but they use windows exclusively).
for desktop software, games and web front-end development windows is king. its the platform that all of your target audience are using to an excellent approximation. for AAA games there is an extra restriction that its the only practical choice (there are zero tools for working on any other platform). sure for iOS/OS X there is the same restriction to a mac and iOS development has become extremely popular - even so there is quite some resistance to using OS X and XCode as anything more than a test configuration on cross platform projects - I've seen a lot of macs dual booting to windows in this context. For android Linux can give you a small edge, but its not much...
Linux is obviously meant for programmers, but that doesn't mean they use it either - until quite recently even the best flavours were horrible user experiences. I think ubuntu is great and really takes steps to get away from the 'you download source and build your app with archaic and buggy tools at the command line' approach which has always dominated... in terms of doing your job though - unless you work on the backend of some web service you can't do any useful builds under Linux, unless you are targetting Linux desktop which is exceptionally rare.
every programmer i know works in a windows dominated environment. this is a small sample though.
i believe that in back-end only environments linux has some serious popularity but i can't comment on how many studios use it as their development platform because i have no great experience there (actually i work in office where they develop such things, but they use windows exclusively).
for desktop software, games and web front-end development windows is king. its the platform that all of your target audience are using to an excellent approximation. for AAA games there is an extra restriction that its the only practical choice (there are zero tools for working on any other platform). sure for iOS/OS X there is the same restriction to a mac and iOS development has become extremely popular - even so there is quite some resistance to using OS X and XCode as anything more than a test configuration on cross platform projects - I've seen a lot of macs dual booting to windows in this context. For android Linux can give you a small edge, but its not much...
Linux is obviously meant for programmers, but that doesn't mean they use it either - until quite recently even the best flavours were horrible user experiences. I think ubuntu is great and really takes steps to get away from the 'you download source and build your app with archaic and buggy tools at the command line' approach which has always dominated... in terms of doing your job though - unless you work on the backend of some web service you can't do any useful builds under Linux, unless you are targetting Linux desktop which is exceptionally rare.