I don't think there is any proof that the elite connections make any difference on average.

The Dale and Krueger study in fact found evidence that there was no statistical difference in lifetime income for ivy league grads vs less elite schools when controlling for factors like sat scores. In fact, they compared people who were accepted but did not go to an ivy league vs those who did go.

Other subsequent studies by others have seemed to bear that out as well.

So I don't even think that too much can be made of the connections one might make at elite universities.