Subjectively speaking:

1. Pre-LLM summaries were for the most part actually short.
2. They were more directly lifted from human written sources, I vaguely remember lawsuits or the threat of lawsuits by newspapers over google infoboxes and copyright infringement in pre-2019 days, but i couldn't find anything very conclusive with a quick search.
3. They didn't have the sycophantic—hey look at me I'm a genius—overly-(and wrong)-detailed tone that the current batch has.