> Nobody should be submitting unexpected, large, hard-to-review quantities of code in the first place,

Without LLMs, people are less likely to submit such PRs. With LLMs they're more likely to do so. This is based on recent increases in such PRs pretty much all projects have seen. Current LLMs are extremely sycophantic & encourage people to think they're brilliant revolutionary thinkers coming up with the best <ideas, code, etc> ever. Combined with the marketing of LLMs as experts it's pretty easy to see why some people fall for the hype & believe they're doing valuable work when they're really just dumping slop on the reviewers.