Well written, and clear about putting forth ideas that are practical. Wish more thought pieces were written like this. Too bad this topic won't get more attention because it is deemed boring or 'too negative' often.
Why would I use Word or Docs, if I can do it straight with ChatGPT? Why use Outlook if I can send messages straight from ChatGPT? You have a point, OpenAI has a challenge, but this could also be the opportunity of the century - creating a new OS that redefines how we interact with PCs.
All things that will come with time. What makes for a viable product is if the mind is 'tricked' enough into believing it's seeing an actual person instead of a 3D replica.
The more personal value it holds, the more risk it has. Imagine gaining access to this digital daimon of someone, it'll be like accessing their most inner thoughts.
The upside however could be exponential personal growth. I've seen many examples of real life twins that basically live as a superhuman individual. E.g. the Liberman twins. This tech could be a digital equivalent of that.
An LLM/AI companion based on your ledger, that grows and evolves with you, acting as a sort of Socratic daimon, a psychologic twin, assistant, advisor, and sparring partner. Like a journal that talks back and thinks with you. It'd need to be only personally accessible and safe/private. Biometric access and local running could solve this.
This has the potential to be the killer app for mixed reality once instant / realtime translation is possible. Imagine being able to understand every language in the world - and if two users of this product meet, being able to converse without learning each other's language.