I think there's two factors that are worth considering when it comes to this:

First, there's an element of timeliness that simply has hard constraints. In order to perform a "proper" analysis of this situation (i.e., little to no dependence on AI tools), you'd have to expect a pretty long wait. I know I'd rather have some sort of "initial report" as quickly as possible than to wait a year or two to get a report about a situation that will likely look trivial in a year or two. I imagine we'll see more detailed, human-developed reports over longer time ranges.

Second, I suspect the expectation of non-AI driven reporting of these kinds of things will definitely decline rapidly as everything scales up quickly. I mean, the data being produced by situations like this comes in the form of natural language "forum posts" (so to speak), but done at an autonomous scale. This isn't a collection of emails and Slack messages posted by humans in an org over the course of a few months; this is a bunch of bots interacting with each other in relatively novel ways as quickly as possible. It is, unfortunately, a perfect job for LLMs.

None of this disagrees with your points, necessarily. But I just think it's worth pointing out that this doesn't seem like a case of "And look! METR is so confident in LLMs that we're able to use it instead of paying humans to save a buck :D" and more of "Without LLMs, we'd only be half-way done analyzing this data before there are dozens more such investigations on the docket, so this will have to do."