In another way, there's no pressure on Creative because they're the only manufacturers of hardware-accelerated audio.
Vista would've leveled the playing field in this area - but Creative has found a work-around with the Alchemy drivers. But, anytime that there is a strong competitor to Creative that comes along, either the go out of business or just stop produncing any audio hardware. The SoundStorm is a good example - remember the Ensoniq PCI? First audio card to use a multichannel design and DirectSound3D . . . until Creative bought them out.