Strange. Based on the comments on phoronix, as long as its OSS, graphics performance doesn't really matter; Its "fast enough." And everyone uses linux to do "real work" and not gaming. And that if you want gaming, you should be using Windows anyways.
So yes sometimes Win is necessity. On the other hand you DO point at real bulshit replays we can sometimes hear :P
Very few games have a "real" dependency on .NET.
A whole bunch of them use .NET for a useless launcher front-end (Borderlands 2, The Sims 3, Lord of the Rings Online to name three), but a hard requirement on Microsoft.NET is fairly uncommon (examples include XNA games like Bastion, which are ported to Linux etc via Mono). It's also not uncommon for games looking to include C# code to embed Mono rather than use Microsoft.NET (e.g. The Sims 3, any Unity3D game)
True. However, if Linux users want any content creation or mod tools that game companies make, those are increasingly all using .NET these days (and usually with a heavy reliance on embedding parts of the game engine as a DLL using P/Invoke, which of course can be ported to Mono/Linux with a small bit of work). Game editors, art-pipeline tools, and the large array of other tools made for game development all have to be ported to get the full content creation toolbox, and those are more and more often written in C#. This is of course because C# and .NET make it ridiculously easy to build those kinds of applications, even more so than Python or the like (since we generally need a much more capable standard library than Python has, we really really want static typing and generics and reflection and zero-effort native code binding, etc.).
I think the desktop SOHO market is actually prefering MS WOS preinstalled computers in order to play. Not this high end games tested at high res that will not achieve playable FPS at their computers, but some other games at 720p that a 2 years old computer can play.
Android and even ChormeOS are going to be a god share in the computers market, and that makes Linux interesting for game developers, not for the 1% of SOHO users, but for the multiplattform development.
And of course because the cost of MS WOS is very high for emerging markets and a lot of new computers users will buy ubuntu preinstalled at low power and cost machines, even arm ubuntu ones for their soho desktops. Machines not able to run MS WOS 7 or 8 properly, but that can run very well with Gnu Linux.
And also the ARM Linux at PCTVs that, as it increases not a lot TV prices, will be soon a "normal" product.
And it is more important, the recent Samsung policy for their GPUs of OPEN SOURCE drivers with GPL and Apache licenses, than that AMD and NVIDIA must copy this policy if they do not want to loose even the PC market in a not very long term with PCI multi GPUs designs coming from mobile GPUs.
Adding Wayland to this scenario, and perhaps some open source Android Compatibility Layer for playing android games on Linux, having a GNU Linux installed will be soon a must have for a SOHO gamer, and even perhaps for a high end PC gamer.
And if it happens, perhaps MS WOS will be an option in a long term, V9 or 10, who knows.