Kagi actually does an interesting implementation for their search summary and while not perfect, it is miles better than the alternatives in my experience. It uses a combination of anthropic's claude for language processing as well as incorporates wolfram alpha for stuff that needs numerical accuracy. Compared to google AI or copilot I've been seeing good results.

While it isn't perfect at summarizing, I've found their implementation to be "good enough", and it can summarize pieces near instantly, which I think is the place where it actually becomes useful. Humans may be better, but I dont have the money or time to pay a human to summarize pages for me to see if they're going to be useful to delve further into.