You can't assess anything until college is over and you are actually in the real world. Good Grades does not mean you will succeed in real life. It mostly means you are good at following orders.
The savvy employers do this—though probably not enough. There's a finance firm that hires exclusively Math 55 [1] alumni—I forget the name; a number of tech firms screen for CS161 [2]. Both among the hardest classes you can find. An A in those takes a hell of a lot more than just following directions.
[0]: http://harry-lewis.blogspot.com/2014/11/can-we-find-better-w... [1]: http://en.wikipedia.org/wiki/Math_55 [2]: http://www.eecs.harvard.edu/~margo/cs161/
Maybe if you went to a terrible school. In any decent school it means you were able to come up with a solution to a problem presented to you. This is especially true for upper-level classes where the majority of the grade is based on a personal project.
Starting and completing a huge project that doesn't have deadlines where you have to figure out how to bring it from idea to market is real, and it rarely takes a semester and it isn't at the discretion of a single person to look at it for 30 minutes and then put a letter grade on it, and then throw it in the garbage. The most important difference though is that amount of effort only loosely correlates with the success of a venture in the real world. In school you can really just brute force most problems.