The hypothetical was meant to show that your analysis was insufficiently sensitive, not to posit that the hypothetical was actually the case.
You have an odd habit of pointing to secondary and preprint material, rather than the primary literature. Your APA links to several papers, including http://www.drtomascp.com/uploads/HungryMind_PPS_2011.pdf , titled "The Hungry Mind: Intellectual Curiosity Is the Third Pillar of Academic Performance". It concludes:
> The current study suggests that traditional sets of predictors of academic performance, notably general intelligence and Conscientiousness, should be accompanied by a third factor: intellectual curiosity. Jensen (1998) stated that “[general intelligence] g acts only as a threshold variable that specifies the essential minimum ability required for different kinds of achievement. Other, non-g special abilities and talents, along with certain personality factors ..., are also critical determinants of educational and vocational success” (p. 544–545). A remarkable number of studies on determinants of academic achievement have focused exclusively on ability and effort; the present findings, however, recommend further expanding the “g-nexus” for a better understanding of individual differences in academic performance. The latter requires—beyond intelligence and effort—a hungry mind.
It does say "intelligence is the single most powerful predictor of academic performance", then said:
> intelligence sustained the strongest effect on academic performance with a path weight of .35. TIE and Conscientiousness had slightly lower, identical path parameters of .20.
I believe that means that the other two legs together are more important than intelligence alone.
Then, we would expect that there would be little correlation between testing scores and outcomes. Especially whether they get a degree. For instance, someone who gets a lower test score will have the same outcomes as someone who gets a higher test score.
But that's not what the research suggests:
> The report, which examined 1,753 studies, found that GRE scores could help predict students' graduate grade point averages, first-year GPAs, ratings from faculty, exam scores, degree attainment and number of citations earned. The specific subject tests were even stronger indicators of students' performance.
http://www.apa.org/gradpsych/2012/09/cover-success.aspx