The original author's point is interesting, seeing rules as the constraints that, in one sense, spur creativity, give life. The reason the trumpet is the instrument of jazz isn't in spite of it having merely three valves, but because of it.

In answering whether Nguyen's argument holds, Runciman decides Nguyen isn't talented enough to be worth judging, then judges him anyway. A book about scoring systems gets scored on the wrong axis. Runciman then uses this to great effect, blending this silly aesthetic complaint with a real structural one.

The structural point I even agree with. You can always take up a new game, but at the social level there is often no other game to play, and you can't opt out of a metric that has power over you. But Runciman doesn't trust the point to carry the piece, so the verdict on Nguyen's prose is enlisted to stand in for a verdict on Nguyen's case.

The irony: to fault the book for not being "compelling reading" is to let a convenient proxy displace the value it was meant to track. That is "value capture" as Nguyen puts it.