"For the past year and a half or so, ATI and NVIDIA have fought a hard battle over leadership in the desktop graphics market with very little in the way of outside competition. Before that, NVIDIA held a comfortable position in the industry after 3dfx started to struggle. There is the occasional release of a Matrox card, PowerVR poked around for a little while, and the ultra low end "just VGA" market has always been filled with the likes of Trident (bought by XGI last year). The desktop graphics arena is filled with the bones of companies who have tried to gain a foothold in one of the most greusome markets in computing. Six month product cycles and always staying one step ahead of the competition is not something that many companies can surive. "
Anandtech