Perhaps some on the OpenAI leadership team know the answer to this question.
OpenAI currently have advised everyone to make backup copies (however users wish to do so) of ChatGPT sessions. This is the best way to insure you have access to them in the future.
This will become easier for ChatGPT users when the (coming soon) ChatGPT API is released.
Not sure, but I would back them up. This was in their announcement for pro today…
We love our free users and will continue to offer free access to ChatGPT. By offering this subscription pricing, we will be able to help support free access availability to as many people as possible.