People who want to cheat will always find a way to cheat. All you need to do now is go to the bathroom and lookup answers on your phone.
How does this contradict the GP? This doesn't necessarily seem inconsistent with standardized tests correlating better with academic success on its face. Because I would expect that such people tend to have not just worse standardized test scores but also worse academic success (because of the advantages that wealthy people have that these people lack).
If someone with a high aptitude but low academic performance is put into a situation where they have more access to resources, they will perform better than someone with low aptitude that has the means to make up for it in their academic success.
For instance, the popular college prep hack is take the SAT three times. Study for a different section each time, and colleges will take your highest score of each section. That’s not possible without the moderate financial means to take the test multiple times.
Your average high school student does not have thousands, let alone tens of thousands, of dollars at their disposal to cheat on the SATs.