Funny that you regard people who disagree with you as being cognitively challenged. I understand exactly what you are saying, and I am disagreeing with you because I think it would be a bad thing for Plex to waste their limited time and money on the requested feature.
a) I use Plexamp quite a lot, so I do have an interest in its development. Flawed as it is, it’s pretty-much the best tool out there for doing what it does - play music from both ones own collection and a streaming library service. I want to see its handling of music improved, and I don’t want to see time wasted on audiobooks because it would suck oxygen away from its core function, which still has plenty of room for improvement.
b) I think the idea of turning Plexamp into an audiobook player sucks. The UI requirements are just so completely different from music listening, and if you want to consume audiobooks out of your plex library on your mobile devices, there are already fully-featured player solutions out there. A separate Plex Audiobook player application would make far more sense than creating some kind of hybrid app that does neither task well. Even that makes little sense without a serious upgrade of back-end support for the media type.
c) As of right now, Plex is not a good server for audiobooks. It just does not have a good way of handling series, etc etc. It could be a good server for audiobooks if it recognised them as a distinct media type. Then, and only then, would it make sense for Plex to try to get into the market for audiobook player applications.
I’m not sure where you got the idea I was thrilled with the Audiobookshelf player. It is actually pretty bad. But the Audiobookshelf back-end does at least have metadata concepts applicable to audiobooks and represents a worthwhile direction that might one day be a good server.
Believe me I’ve done my googling to see how others try to bend Plex (and other servers) to handle audiobooks well. They seem to rely on having rigid directory structures and/or abusing ID3 tags by using them for things they were never intended for. Hardly a good solution because setting up your library for one server implementation potentially breaks it for all the others. That said, I am serving my audiobooks to my player from Plex quite happily right now.