Quote - "This is an aspect of the modeler's skill and inventiveness, not some objective concept of "perfect topology"."

Nope. It is an objective mathematical problem.

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You are absolutely right! The perfect mesh IMO is exactly square and consists of a single polygon. I have never seen a render that could not be accomplished by using a single (properly textured) quadrangle. Everything else is a compromise between different aspects, like e.g. memory consumption, morphability and sought income of the modeler, whose job is to make those compromises to satisfy very different requirements of varying customers, and which unfortunately cannot simply be expressed as a mathematical problem.
However i imagine that there are some people who are of the opinion that the perfect mesh is not a quadrangle, but a triangle, but i do not think they are right.