I imagine that's an understatement. Using only the written works available from before Einstein (let alone Newton or Plato), you'd probably need a whole new technology that could train itself without any training data other than observation of the world.
Where's the learning robot that I can teach to drive a car in the same way? They can solve some complex math problem but can they read the cues of other drivers at a four way stop to know when they should go (knowing the rules isn't sufficient).
Can we even measure an intelligence greater than our own? And at that point -- what is the point exactly? Why make an intelligence that we don't even know is intelligent? If its output is indiscernible to the human mind, what good does it do us?
The only "barrier" I can see that is valuable and that might be measureable to humans is this underlying mechanic of being able to create new ideas/concepts from little to no existing human generated training data. Otherwise, and as I see it right now, these machines will not become sentient, or go rouge, or be able to cure all future disease or solve all of physics, becasue they are entirely reliant on human made trainingsets.
Historically, for humans, this can not be the case, otherwise we would see no progress. Someone has to have a thought for the first time. Perhaps the solution to this for AI agents is some inherent randomness, and massive amounts of brute force compute. Who knows?
We can always just unplug the computer, you know. AI agents can do damage, they can be used in malicious ways and bring down/distrupt infrastructure, but the leap from today to the point where LLM's can prevent us from pulling the cord is unimagineable large, and likely infinite.
In modernity, the gap between the digital and material world is closing, especially from a sociological perspective, but we are still neurological systems spinning on a large rock. For 99% of our history we didn't have electricity. The likelyhood of returning to a post-electricty world, for example, is much greater than LLM's taking over the world and making us into zoo animals.
It is becoming a boring homogenous world where we are trading deep expertise with being able to query the magic box
My guess is that you can find 99% of Maya pyramids in a Lidar set in a fairly short time with a traditional neural network, but you might find the last few using a network of AI agents, because they are capable of "creative" problem solving and using different methods/parameters/tools over several iterations.
You train a cat-classifier, and they will fail for a plush cat. Or maybe fail the other way, but not realizing it should also report a plush cat.
LLMs are much more robust, "find only the real cats in this picture" or "find all cats, including artificial/drawings/..."
And yes, you can add more training data to your classifier, but it's a never ending battle.
With LLM you unlock a whole new world of possibilities regarding the speed and result but we are also finding ourselves in a position where "asking the LLM" because the cheat for everything, no reason to dig further
The final barrier for super intelligence, or perhaps even just "human intelligence": can it materialize "new fields/ideas" without large datasets of human made and curated existing attempts?