for their image yes
but it's not where the big bucks come from
since, let's face it, MultiMonitor Gaming while pure awesomeness is even more "elite" than highest end GFX card
and we all know high end gfx card are not selling as much as medium and low end ..
True.
However:
Many buyers will base their purchases on who they are told is the best. If ATi or nVidia have the best top-end card, their overall sales rate goes up across the board. It's only enthusiasts who look at the cards in question. Seriously, this phenomenon is well documented: if you have the best top-end, sales at all points in the spectrum increase.
Furthermore:
Notice how TFT's went up in size fairly quickly? 1280x800 to 1680x1050 to 1920x1200 to 2560x1600... but then topped out. The cost of displays with higher resolutions thatn 1920x1200 is prohibitively expensive as the greater number of pixels, the higher the chances of getting multiple failed transistors in the matrix... (dead or stuck pixels)... so I'm thinking that in the quest for ever more resolution, the short term fix is going to be fairly-cheap-multi-screen.