DO Good Grades Predict Success??

After reading an article, Do Good Grades Predict Success, as posted by Stephen J. Dubnar on the blog "Freakanomics", in which Dubnar addresses the fact that good grades throughout school cannot ensure success, I began to think about the subject myself. Although one may have great grades throughout school, is does not prevent them from ending up homeless or flipping burgers at McDonald's. At the same time, one could not have the best grades or even fail a few classes, but still turn out to be a big shot. Let's take Albert Einstein for an example. Everyone knows who he is, he discovered major scientific ideals, and failed Latin in grade school, which goes to show that grades don't mean you're a success or a failure. I am certainly not implying, however, that one does not need to care about their grades for, also stated in the article, persistence is one of the main things one should learn out of failure. If one does not endure the strife of making and maintaing the grade in a subject where they are not strong, then what can one endure in modern society, where everything is fast-paced and people are willing to step on you to get the extra $100 at the end of the month?