That is simple:@Svartalf: maybe you should rethink that anti-buying-a-Windows-version thing that you keep repeating, since you're not offering a viable alternative saying that something is bad is useless, you are not answering the question that follows: "OK, i won't buy the Windows version, where from do I buy the Linux version?"
Do not buy it (and thus play it) unless there *is* a Linux version. Once the Linux version is available, either via pointrelease or "real port" by a different company, buy the game. Best would then even be to buy it in a "linux shop". There are several of those out there, eg ixsoft.de or tuxgames.com.
It is basically every players own choice. Either wait until a linux binary is out (yes, it might be "forever") or buy a Windows title which is only available for Windows and support this market.maybe it makes you feel good to show everybody the truth, that buying means accepting, but that good feeling that you have does not replace the games that we all missed playing in Linux or in the ( wonderful but ) broken WINE
Let's make it a simple calculation from the publishers point of view:
If you saw that you have many sales of your product, why do create a Linux port? Why do this while there are many Linux users buying it to play it via wine? Why invest the money needed for the port? Yes, if those were not buying at all, this might be a starving market where I could gain a lot of profit with little effort, but why should I do so when 70% of the users buy my Windows version, too, without me putting a single dollar in it?
The harsh truth is that wine actually is hurting the Linux market for many native products though the software itself makes lots of sense. So if you wanted to explicitly support Linux gaming, you would just buy and play those having a native Linux version. (For example you could try to open source shooter or, to have something different, a turnbased strategy game in a fantasy theme, more commonly known as "Battle for Wesnoth" [/shameless advertisement]).