I get your frustration, however it’s important to understand that given finite resources, it’s necessary to prioritise some features over others.
In the last ~ 2 years, off the top of my head, the following music features (and many more) were released:
- Plexamp 3 (and many, many subsequent updates)
- Rewritten and much improved Plex Music agent
- Super Sonic analysis
- Sonic Adventures
- Smart Collections
- Many, many improvements and fixes in PMS for music (see PMS 1.23.3 for a good example of some of these changes)
The devs aren’t ignoring you, or sitting idle while their code gathers dust, they’ve just been focused elsewhere 
