"But can't AI just be used to complete unimportant backgrounds or clean up animation?" No. Those are entry level positions that turn into long careers. Bg painters become art directors. Clean up artists become animation leads. Stop trying to cheat.
“your patience will be rewarded” to someone saying they want the trailer is a very vague statement and is just meant to create buzz (and succeeded). it does not insinuate anything concrete imo, but they’re probably commenting now bc it is dropping soon! (like we all thought)