You are assuming that because we measure an undergrad's ability to critical think with undergrad essays, that is a valid test for the LLM's capacity to think -- it isnt. This measures only, extremely narrowly, the LLM's capacity to produce undergrad essays.
Society doesnt require undergrad essays. Nor does it require yet another webserver, iot script, or weekend hobby project. Society has all of those things already, hence the ability to train LLMs to produce them.
"Society", the economy, etc. are operating under competitive optimisation processes -- so that what is valuable, on the margin, is what isn't readily produced. What is readily produced, has been produced, is being produced, and so on. Solved problems are solved problems. Intelligence is the capacity of animals to operate "on the margin" -- that's why we have it:
Intelligence is a process of rapid adaption to novel circumstances, it is not, unlike puzzle-solvers like to claim, the solution to puzzles. Once a puzzle is solved so there are historical exemplars of its solution, it no longer requires intelligence to solve it -- hence using an LLM. (In this sense computer science is the art of removing intelligence from the solving of unsolved and unposed puzzles).
LLMs surface "solved problems" more readily than search engines. There's no evidence, and plenty against, that they provide the value of intelligence -- their ability to advance one's capabilities under compeititon from others, is literally zero -- since all players in the economic (, social, etc.) game have access to the LLM.
The LLM itself, in this sense, not only has no intelligence, but doesnt even show up in intelligent processes that we follow. It's washed out immediately -- it removes from our task lists, some "tasks that require intelligence", leaving the remainder for our actual intelligence to engage with.