This varies a lot by place too. Where I live, lots of developers choose to use Windows. Fashion and momentum matters.
> are either writing Windows software
I assume most people in the game industry need their game to run on Windows or use hardware that only works with Windows (like a dev kit for a console).
Unless you are talking Web and mobile games, in which case, most of the web gave devs I know use Mac and so do most of the mobile devs (thanks the the difficulty deving for iOS on Windows).
But that is why I called it an "anecdote"... your milage may vary.
If it is because I said "any tech conference"... if so I humbly beg for your forgiveness for using an absolute when I meant to be anecdotal. I thought people understood hyperbole. In any case, it would have been more productive to post a comment... "actually my experience at tech conference has been different" rather than down vote.
Personally I reserve my down votes for trolls and off topic posts, I don't even use it for people I disagree with, but to each their own. I accept your judgement.
I imagine it is dependent on major.
Go to any tech conference and it is 90% Macs as well and a good portion of the remainder is Linux. But I'm guessing other industries / fields of study are mostly Windows.
The only developers I know still on Windows are either writing Windows software or using hardware that only works on Windows. And even some of them use a Windows VM on Linux or OSX. That is of course anecdotal.