True. There should be some form of correlation, that is to say that people with very low grades usually aren't that good. But e.g. difference between 4.0 and below isn't related to talent. These people usually are good at studying, not at a special subject in itself.
Besides there are...
I was curious, about the relation of grades to high achievments. It's safe to assume, that most Nobel Prize winners for instance had rather high grades. Does anyone know if there has been studies of grades of high achievers?
More in particular, where can one find the grades of Einstein...