Just a few years ago, you would never see such a disparity in votes vs comments. But these days, this is pretty much the norm. I've seen posts with 10K+ upvotes and no more than 80 comments.
I'd say in about 2 years, the entire place is going to be bots with AI generated content that try to mimic "real users" using their new Dynamic Product Ads tool. Not sure how that's legal as I thought ads needed to be marked or differentiated from regular content, but here we are.
The future looks bleak and AI even bleaker. Because it's going to be used against us to make the rich richer and not to make our lives better.
I think one has to gather more proof before concluding that the gap is due to LLMs. It can also be that the engagement was lost due to third party app drop. We don't have stats to distinguish them.