Photobashing was hated to death when it was new. Now it's the norm (for environmental concept art at least). AI will go through the same process.

AI is the norm for concept art already, it's too useful for it not to be.

I don't know what sort of artists you know, but of all the artists I know, nobody is "completely fine" with tracing. It is okay but still frowned upon when people do it for "practice" without publishing the result, but anything that even looks remotely like it is traced gets called out and further investigated incredibly quickly.

And as for fan art, a lot of companies explicitly allow art based on their IP, as long as it's used/published by the artists themselves and the commercial rights to the work aren't sold to some other company. In Japan, there is a whole industry based around derivative works, Doujin - self-published works, that works off of what is essentially a code of honor. Companies don't go against the artists, as long as said artists adhere to certain guidelines on what they're allowed to depict (eg. no NSFW content.) Many franchises have become a lot more popular due to fan art/derivative works alone (ie. Touhou Project, Fate Series.)

Tracing is particularly unacceptable in professional settings. There’s been several cases, some even somewhat high profile, where manga and comic artists have found themselves in hot water as a result of engaging in the practice.

>Tracing is particularly unacceptable in professional settings.

Tracing is a fundamental skill in a professional settings for consistency, speed, and quality reasons. In torepaku it is the paku (pakuri) part that is not acceptable.