Even if ‘markets with decentralized decision making often beat intelligent design’, that doesn’t mean decentralised decision making dominates centralised planning (what I assume he means by intelligent design)
But ChristianKI is neither claiming nor implying that (so far as I can see); his point is that Eric is arguing “look at these amazing things; they’re far too amazing to have been done without a guiding intelligence” but his experience in economics should show him that actually often (and “often” is all that’s needed here) distributed systems of fairly stupid agents can do better than centralized guiding intelligences.
(I don’t find that convincing, but for what I think are different reasons from yours. Eric’s hypothetical centralized guiding intelligence is much, much smarter than (e.g.) the Soviet central planners.)