What? They did have onboard sound. The problem is that if you used the motherboard speaker to make anything more decent than a beep, you basically needed to build an entire sound engine from scratch and very few games did so. It also wasn’t worthwhile because a shitty two pin speaker could not compare to the speakers of a professional sound system which you needed the soundcard to hook up into, and CPU bandwidth was such a limitation back then than even when games could play WAV they would use MIDI to offload the musical instrument synthesizing for the soundtracks to the sound card. Designing a game that used the onboard sound speaker was basically the realm of assembly hacking geniuses.
What? They did have onboard sound. The problem is that if you used the motherboard speaker to make anything more decent than a beep, you basically needed to build an entire sound engine from scratch and very few games did so. It also wasn’t worthwhile because a shitty two pin speaker could not compare to the speakers of a professional sound system which you needed the soundcard to hook up into, and CPU bandwidth was such a limitation back then than even when games could play WAV they would use MIDI to offload the musical instrument synthesizing for the soundtracks to the sound card. Designing a game that used the onboard sound speaker was basically the realm of assembly hacking geniuses.