Matrox seemed to have little if any success getting game companies to make this a priority back in the Parhelia days. In fact, I think I remember them pulling there game developer liason off that responsibility at some point.
Has this changed at all with TH2Go? Any idea if they are making headway?
I think the problem back then was everything was 4:3. There frankly was very little reason to change aspect ratios. Widescreens are still coming into popularity, and game companies now realize that they need to be flexible with aspect ratios or they are going to lose sales.
Once you break the mold from 1 aspect ratio to 2, it is very easy to say "while we are at it lets add TH2G resolutions." For example, I have not run into a game yet that natively supports widescreen that did not support TH2G natively (granted I'm still exploring and new to the market).