In the age of the machine, judgment is the last moat. Rote expertise is the first thing automated — the machine is a peerless specialist, and what it does first is absorb every domain whose value lies in fluent, recallable competence. What it cannot supply is taste: knowing what is worth building, which domains to braid, and when to stop.
Taste is the working face of the arithmetic of breadth. Combining fields only pays when someone can tell which combinations matter, and that telling is judgment, not coverage. The machine will answer any question put to it well. It still cannot tell which question was worth asking.
So the moat is not knowledge but discernment. As stated in The Generalist Manifesto, the machine is a peerless specialist that still cannot tell what matters — and that, for now, is what survives.