I went to my audio dealer yesterday, a large store on two levels, and they only list two DACs on their website - the dCS Vivaldi DAC and an Audio Research tube DAC. They sell dozens of speakers, amplifiers, streamers etc., but just two DACs. Another dealer I have used listed only Bricasti and Chord and a load of headphone amplifier/DACs.
Standalone DACs were originally intended to isolate the drive in CD players, the first outboard DAC being from Cambridge Audio in 1985. I had a Marantz CD player than had an optional outboard DAC. Standalone DACs were mainstream, but seem to be falling fast in popularity in favour of digital processors with a streamer and DAC as a minimum, plus other options, such as pre-amp, transport, analogue inputs, and various DSP. The massive disadvantage of separate digital boxes is connectivity issues.
Now that PS Audio is finally about to launch a proprietary streaming product, I live in hope that it will get around to making a proprietary streamer/DAC in one box, with volume control, at both Jnr and Snr level.