People think that the bell curve works to magically bucket people into different grades. But the truth is, a large enough population would naturally follow the central limit theorem.

The fact is that there can be 10% of the population in the top 10%, and 10% in the next 10% - and grades are awarded accordingly. If 50% of the graduating students were to receive A, how would we be able to distinguish them? You may argue that all 50% were equally deserving of that A, but ultimately some are better than the others - there can only be 1% in the top 1%.

This is mirrored in our society. You will experience this immediately after graduating - if there are 100 applicants and the company only has time to interview 10, given all things equal, it's not hard to imagine that they would interview the top 10.