I fear one issue is that #FOSS folk (unless they have a special interest in them) generally consider #telephones uncool (in spite of these still being widely used in ordinary businesses), and many commercial #VOIP engineers themselves are now working for #SaaS companies and want to nudge small/medium businesses towards #cloud services to gain a constant revenue stream from per-user charging, so they simply aren't sharing knowledge that would cost them potential business or be useful to competitors (and all this has already been going on for 15 years, way before #AI became a thing)
OTOH it seems things like general #coding and even #retrotech might have enough training material for #LLM to give something approaching a correct answer to a prompt..