I'm a little out of my depth right now, but it is my supposition that the media server expects this format and 3CX would have to rewrite the service (and likely others) to support other formats. Further, you could also argue that optimizing audio to work best over analog POTS lines is less important today, however, we have to remember that 3CX is an international company with customers in countries where POTS is still common, if not the primary mode of transport.
I also assume that if this was easy, 3CX would have added support for higher quality audio files a long time ago. However, if you stop to consider how many places in the PBX touch audio, you might start to have an inkling regarding what a huge undertaking this would be. Then you have to ask yourself is this the highest priority, or are there more pressing demands on the development team?
Heaven knows having voicemails in a low quality audio format wreaks havoc with voice-to-text engines too, yet here we are trying to serve multiple masters -- support for the best possible voice audio, while supporting lower bandwidth options like analog, and at the same time trying to prioritize issues like bugs, performance, scalability, multi-tenant features, and the list of "critical" needs is surely very, very long.
As you have noted, this request has been around for a long time. But we also have to recognize that the industry demands are changing daily and maybe optimizing 3CX for multi-tenant hosted platforms is even more important... or something else. I for one would much rather they spend time on a REST API, than on higher quality .wav files... and that's my point. What we think is the highest priority is only a couple of inputs into the priority list. Nick has a long track record of directing very successful businesses and I am confident that he is making priority decisions based on what is best for the platform with a very broad view of the future. In light of that, your demands and mine are certainly on his radar but they just have not bubbled up to the top of the list yet.
It's good to keep our pet projects on Nick's radar by providing input through your 3CX representative, and here on the forums. Keep going. But the fact that you are here as either a 3CX customer or partner is an indicator that 3CX, Nick, and the Development team are getting many of the priorities right. As an owner of a software development company myself, I painfully acknowledge the fact that as long as labor and time resources are finite, there will always be competing priorities.
