What do you think? Assuming this is a thing that can and will occur, what impacts do you think it will have on culture, fandom and individuals? And would you employ such a service?
I think it would (will) find a happy medium in the culture. Given the proliferation of forms of easy entertainment available nowadays, however, I suppose it could end up diluting entertainment media to some degree.
I don't think that, movies, TV series, novels, team sports, video gaming, etc, are going to disappear. That's just because part of what makes "culture" culture is the shared experience of such things. Some people will strongly gravitate to bespoke fiction, and others will be repelled by it, and everyone else will float in the middle somewhere. Eventually AI-gen would just settle into its "natural" place, wherever that is... probably be a similar place as fanfic or fantasy football or some other niche?
Also, as independent (open source, free, etc) generators, I doubt such AIs would ever get terribly big simply due to regulation and/or control by the companies that create them. So I can imagine established brands engineering custom AIs to give fans bespoke fiction within that universe. For example, Disney might (try to) sell a subscription to their AI that would churn out Star Wars graphic novels or animated shorts featuring characters (existing or generated) within the Star Wars universe, but who are constrained by the AIs guardrails to operate inoffensively and solely within official canon. On the other hand, I suspect that free/open AI projects would likely remain pretty small scale, rough around the edges, and serving a fragmented niche. Branded or not, though, solely AI-gen media just doesn't strike me as something that would change the entertainment media landscape too significantly, tbh.
As far as how it might impact the volume of new works by human creators, it's not clear to me that AI would change much of anything at all, except maybe in the tools used by those creators. I mean, a fundamental part of being human is that people like to create, so they would continue to do so. Of course, people also need to pay the bills, so imo examining that particular aspect of AI on culture is more difficult in a hypothetical world mostly free of economic concerns.
Would I use such a thing? I doubt it. Most of what I do consume is recommended by others, not what I'm "in the mood for" right now. HOWEVER, my exception: computer games. I would be definitely interested in AI-generation (eg, imagery, plotting, rulings, and maybe audio) in solo CRPGs, especially relatively lightweight turn-based games (eg roguelikes) that I could tune to my my own thematic and mechanical preferences. Some of this sort of thing has already long existed to a degree, but I think AI promises to make those types of games MOAR!! in ways that would likely appeal to me. But that's another pretty niche thing, too.