You can dig through every single paper and find some citation that was missed. No one cares that much unless the result is important, and then you get bitter recriminations saying that it was stolen or plagiarized. Tale as old as time. See e.g. Schmidhuber, who has a long list of vendettas against people he thinks stole his work.

The existing, human standards are based on human capabilities. Humans may not have read all the papers that could be cited. However, all these papers are almost certainly in the AI’s training set and it potentially has the ability to retrieve them over the internet into its context. Why shouldn’t we expect the AI to cite more comprehensively?

It seems more like a goal-setting problem, than an actually novel one. But a paper with lots of citations is not as “cutting edge”, so maybe doesn’t make sense for marketing reasons.