Competition certainly sounds nice on paper, but think of the problems that the various sound servers/api's have caused. OSS(+ 4Front's version), ALSA, PulseAudio, Jack.
I get that, but Pulseaudio has also ruined my day more times than ALSA has... so as far as my specific requirements go, I'm not sure what exactly it's supposed to achieve. It's just sort of foisted on me if I pick the wrong distro.
ALSA is monstrous to configure, but capable.
JACK serves a very specific purpose for music production.
I'm still not sure what pulseaudio is for, but I don't think I'm the target audience for it.
Point is, they don't exist contrary to each other, but in parallel and often in concert.