> "How can a human designer compete?"
and the (related, but as noted by @marc_io nearby, quite different) claim:
> "inevitable that this would impact on the demand for human artists, and I think this will start soon"
both need a more careful look.
Regarding the "designer" part -- most people aren't really very good at design and illustration, and adding computers doesn't always help. See, GeoCities home pages, or your favorite desktop publishing real estate agent ad.
People do get tired of sameness in images, and their eyes like new things, personal styles, clarity, chaos, whatever. That's one of the things designers do. See the Helvetica documentary for more [https://www.hustwit.com/helvetica].
Point of comparison: Geoff Hinton's careless claim, made in 2016, that radiologists would be displaced by 2021.
[https://towardsdatascience.com/why-ai-will-not-replace-radio...]
[https://statmodeling.stat.columbia.edu/2021/06/07/ai-promise...]
This tech will have an effect, but thinking that design (or, breathtakingly, "art"), is now a solved problem and we can move on, seems premature.
A re-watch of the Helvetica documentary might help here. Desktop publishing changed print design but high-impact print (or 2D) design is still very important and not left to amateurs, for good reasons.