No one has ever built a historical model that predicts the future with any accuracy. There are plenty of overfit models that "predict" the past, but none hold up on new events.
but it is about, like, some measurable things about society, which is based on past observations, and it has been somewhat predictive? (though, perhaps it being somewhat predictive has been in part due to it becoming somewhat prescriptive?)
Moore's law is more of an economic necessity. Circuits get cheaper to run, cheaper to make, and faster the more you shrink them, so you just keep shrinking them. This was observed by Carver Mead way back in the middle of the 20th century.
Moore's law requires an average of 3% increase a month in the number of transistors packed on a chip. With a few hundred thousand people working on the problem, that's not crazy. Of course it's going to be spikey, but combined over the lifetime of a chip project...
I don't know that Moore's Law is what most people would mean by a historical law, but it has held up surprisingly well even for a non-historical law :)
Just because it has not been done before, doesn't mean trying to do so (i.e. make a science of history) is invalid or just cargo culting. Especially since GP referred to other social sciences, and named neuroscience. It has not been done for history, maybe it never will be. I don't think generalizing this to all social sciences holds up. Surely there are some falsifiable predictions of psychology, sociology etc that has been tested.
Interesting book on the topic from the world's leading researcher, if you're curious: https://www.amazon.com/Superforecasting-Art-Science-Predicti...