Didn't want to overshadow PCM then market it as a lower cost alternative? Hard to say but I know AFM stereo was around as it was used for the semi-pro market line like the Sony EVV series. Could also be the PCM side was seen as something of a failure as the AFM stereo had a better sound and didn't need the DBX companing. With Sony anything is possible.
My answer to the small formats:
https://audiokarma.org/forums/index....0-jpg.3005489/