Earlier quoted context omitted.
Direct connections for audio or video calls are a patented ‘invention’ that is why the major vendors like Microsoft and also Apple changed to server based communication.
There were a number of patent trolls that tried to milk this but if I could resist them then certainly so could the likes of Microsoft. This is definitely not the reason for the switch. See also: https://jacquesmattheij.com/my-brush-with-a-patent-troll
Unlike these big companies you probably don’t stand to lose half a billion dollar. You’re just going to go bankrupt.