I think the matter is that:

• all main UT contributors are aware that VoLTE is that many people need (and those who don't need it yet are going to need it eventually),
• the project has been working on it for years,
• but sadly it's difficult, because even if you get it to work, it's usually per device, and even when VoLTE works on a device on one carrier, that does not mean it will work on every carrier.

Also, being asked / or even encouraged again and again about one thing, can lead to burnout and will definitely not bring up happy feelings.