It's not that important now as AI took off the ground. New models can be trained completely on generated data. That will give them core abilities. Real world knowledge... whatever humans can get models can.
How does that account for all the things that change in the world, but in ways only humans can observe?
How can AI discover that a beloved tourist destination has turned to crap, or that the best vacuum cleaner of 2022 has a new challenger, or that German tipping culture is shifting, or that the café down the road has great banana bread but is a little loud on Saturdays?