Thanx for the link.
I did noticed that the artcle is 5 years old and alot had changed sice then.
First HL2 wosent even anaunced to the public and the TF2 screens from that time resemble nothing of HL2 state today. From what I understand for some time TF2 was supose to be a stand alone sequal but later was scraped in fawor of HL2 and porting every thing to the Source engien.
So IMO their is still hope left. If Doom 3 has Linux client (wich knowing iD their is a good chanse of that)Valve wouldnt whant to miss out on that market it self.
Also alot of home/dedecated servers for HL and CS use Linux it would only make sence their are also Client users who would by the game as well.
Dose are just my observations.