For what it's worth in early 90's people were playing PCM audio on PC speaker, which is single bit DAC that is in turn controlled by programmable interval count

For what it's worth in early 90's people were playing PCM audio on PC speaker, which is single bit DAC that is in turn controlled by programmable interval counter and thus effectively cannot even directly produce single bit PCM. Norton Commander (5 or so) even included PC-speaker WAV player. Edit: also having only one bit can be offset by larger sampling rate. In fact this is how probably every non-audiophile audio DAC manufactured in last 25 years works.