I don't think being able to play multiple sounds simultanously from the desktop in the Win9x era was that common anyway although some sound cards probably supported it. I do find it useful for playing my own music while playing a game or watching some talk-only video and so on. Never had any issues with OSS or ALSA so I can't say audio "always having issues" before PulseAudio matches my experience at all... Maybe that's referring to ESD.