They should pair with openai: gpt4, text<->voice, image generation and plugin to track player attributes is all you need, no?
2. Current GPT based DMs allow the player to do basically anything they want. Human DMs offer more control over the game, and will follow closer to tradition and unwritten roles than GPT allows. There's also a fun part of the game for the player in which they convince the DM to allow an action they wouldn't otherwise.
3. D&D's low tech nature is a draw for a lot of players. Some books, some paper, pencils, dice, a table. Simple stuff. I think many players would push back on screens and other high tech.