Let's forget about ChatGPT and other AI things for a second.
A huge percentage of the users reading this forum, at any time, is usually guest users. Also, a number of those people, probably asked google, electronics (and similar) questions, and it found threads / posts on here, which is why they visited, and in some cases. Like it so much, they become new members.
If we (you), closed this forum, by making it members only (i.e. private), including read access. I suspect, we would lose a huge number of potential new members. Also, some members wouldn't agree with such a policy, so they might move to other pastures.
Anyway, there are many electronics forums. So all it would take is for one of them, to be released / opened up to the upcoming wave of ChatGPT's, for the AI electronics era to occur.
So, long story short. I don't think making this forum private would help, also it may be very damaging to the future (human use), of the forum. As members, are what makes it work. So, anything which has the potential to dramatically reduce the active membership, is probably not a good idea.