The author sensationalizes the effort of the creators, painting a Holywoodesque scenario where they break into every possible software company to steal keys to misrepresent the software, going undetected by every possible security company etc. Since this is a Quora post, I can live with him playing to the gallery.
Given the amount of speculation of involvement of US and Israeli intelligence agencies, and the task this worm was assigned, the real effort might have been just about writing a USB worm that identifies specific machines and handing the USB-0 to a double agent (I stopped watching Homeland after season 5 and am rusty with the jargon). The rest of it would have been simply asking all the associated software and hardware companies, politely, to cooperate.
If any of this is true, stuxnet is anything but sophisticated. Its just lots and lots of specific API calls.
That brings up the question: what is sophistication as applied to software?