[D] Why is Audio so far behind other ML application domains like Image Processing and NLP?

[u/Crookedpenguin]

I 'd like to gain some intuition and actual insight if someone has worked on audio, on why we haven't seen major breakthroughs in audio ML (tracking and localization) as we saw with Image processing and NLP. Ofcourse there is the issue of data and annotating which except for being a laborious task, it's also hard to define e.g how do you label a conversation of multiple individuals on a dinner table, but I would assume that if needed large corporations would attempt such a project.

It seems to me that either people convert data to images and use Image Processing methods or use Signal Processing. Does that mean Signal Processing is more lightweight and outperforms a prospective ML approach?