I had the same thought and found this thread via a search -
Voice ChatGPT could act as all parties - Tower, Approach , and other AI traffic pilots. They can have dialogue between each other that the player can hear and interact with them by voice on the radio channel - it can inject a new voice and personality for each party, and random personality can be ranged based on aircraft type - perhaps you might occasionally hear a new general aviation VFR AI pilot who is a bit slower or unsure and has to ask ATC to repeat occassionally. Accents can be injected to the personalities based on controller location or AI traffic airline. All parties can speak and respond in real time to each other’s voice messages, aircraft movements, weather changes, etc. One AI voice system could be used for a multiplayer group flight, so everyone can hear each other and seamlessly interact with each other and the various AI-controlled parties (controllers, AI traffic).
This is obviously somewhat ambitious but I believe it is technically possible with the current tech, which is part owned by Microsoft. And it would be pretty amazing!