That kid working 25 hours a week to help their family make rent is going to have an easier time buckling down for one test than keeping up their GPA over four years. https://www.usatoday.com/story/opinion/voices/2021/03/23/sta...
I can't really speak to your opinion piece because its behind a paywall
https://theintercept.com/2020/07/05/national-review-william-...
They can, but will they? Plus, it seems like GPA would be even easier for the wealthy to game, many fancy prep schools sell themselves on their ability to place kids in good colleges. If those kids no longer need to perform well on a standardized tests they just need a high GPA, that seems even easier from the school to guarantee.