While it's definitely true that humans are psychology (and not some ideal rational being imprisoned by all the biases), I feel like there's a little chiseling still possible.
Every time I've had a major "wow" moment, I feel like I've dropped something that was in my way, and became a little more of who I'd rather be. I've added a few bits of clay during my life, and sometimes its nice to chip it off, and be able to see a little clearer.
Rather than eliminate, say, the representative heuristic (which would then require us to seek out large amounts of data to be sure of our position) to make ourselves more 'rational', should we instead use the representative heuristic by searching out small datasets that may be artificial but accurately represent what large-scale trustworthy studies have discovered? I don't know how this fits into the marble/clay analogy, unfortunately, but I feel like this is what the quoted piece suggests.
searching out small datasets that may be artificial but accurately represent what large-scale trustworthy studies have discovered
This seems to be what's done by thought-experiments of the form, "If all the world's people were represented by 100 people, then X of them would have condition Y" (e.g. wealth, region, religion, access to resources).
Michael Vassar has been known to say that humans are not 'corrupted' by heuristics and biases and other elements of modern psychology. Humans just are psychology.
Robert Kurzban puts this rather eloquently in his new book:
Michelangelo is famously quoted as saying, "I saw the angel in the marble and carved until I set him free." Some economists are, in some sense, like this. They start with theories in which agents - people - have some idealized, rational mind minus the stuff that economists carve away - thus we see terms like 'biases', 'heuristics', and 'irrationality'. They document departures from (supposed) perfection - rationality - much as a sculptor chips away marble, hoping that when they are done, human nature is left, like Michelangelo's angel.
I see no reason at all to proceed this way, as though human psychology is perfection minus shortcomings. My view, the modular view is more like clay than marble. Like sculptors who add bits of clay, one after another, until the product is done, natural selection added - and changed - different bits, giving rise to the final product. We'll get done with psychology not by chiseling away at human shortcomings, but by building up a catalog of human capacities working together - or in opposition - in various contexts.