As someone who's been on the audiophile ride from the early days of strange use of the PC speaker, and the first FM synthesis boards, I can say honestly say, a few things happened that made discrete audio hardware obsolete:
1. a basic DSP became widely available, to do audio processing
2. storage became vast enough, combined with audio compression, it made more sense to just pre-record all your audio effects and music and play them back through a basic DSP. I seen this shift in games through the years, from old school methods of creating sound effects and music with code, to just playing audio files included with your game.
3. the general purpose CPU became powerful enough to do any complex signal processing and simply use the basic DSP to output the results of the processing.
Basically, in my opinion, specialize hardware is useless in the face of vast storage and general purpose CPU processing. So a basic DSP is all ya gunna need and that's what basically every PC comes with, standard now.