Just to comment that these are not “Middle Class Lives”. These are lives of comfortable affluence in the top 20% or top 10%. A family of four with an income of $250,000 is not “Middle Class”, even if they are below average in the Very Wealthy suburb in which they live.
A college professor in MA has a median income of around $150,000. However, an associate professor (that would be the most common rank of somebody of your age) who did their undergrad at an Ivy will likely do their PhD at a similarly highly prestigious university, and will end up teaching at a university which has much higher pay levels. In MA that is mostly one of the many wealthy private universities or the UMass system, and their income is closer to $200,000 or higher. If the person is a full professor, and/or has an administrative position, their income would be $250,000 and higher, and they are usually families with two working parents.
Of course, most professors do not make that much, but most professors did not attend an Ivy for their undergrad and do not live in the Urban areas of MA. Most Professors live upper middle class lives, with household incomes of around $150,000.
Which ties in nicely to the article. Attending an Ivy League college for their undergraduates can have a huge positive impact on a person who is going into academia. However, that depends on the field, since, in academia, different fields have different universities which are considered prestigious. So in Engineering, attending GTech, Berkeley, UNC, or Michigan provides a much larger number of opportunities than attending UPenn or Columbia, not to mention Brown or Dartmouth.
Of course, if somebody wants to be a faculty member at a “T-50” college in History, an undergraduate degree form an “Ivy+” or a small number of publics, like Berkeley, makes this much much easier. Graduates of these universities also hold the majority of the most influential positions in the professional societies in History (as well as many other social sciences and humanities).
To go back to the reason why grads of Ivies succeed, I’m surprised nobody has mentioned the tendency of Ivy grads to prefer hiring other Ivy grads. It is, of course, not exclusive to Ivy grads by any means. However, since the Ivies were the colleges that were the prerogative of the leadership class, that meant that existing leaders selected Ivy graduates as their proteges and as the next generation of leaders. That is why this tendency has a much larger impact when it is practiced by Ivy+ graduates.
That preference is beyond the preference for people with similar background. A person who sees their own Ivy degree as proof that they are worthy of their leadership position is going to use an Ivy degree to prove the worthiness of people when they select as potential leaders. When the idea that an Ivy degree indicates superiority is shared by a wide swath of the population, it makes this type of thinking on the part of gatekeepers who are Ivy graduates (or not) much more likely.
The articles by this authors and his collaborators look at the long history of the pipeline of “Elite College => Ivy League Law School => Clerking for Supreme Court Justice => being a Supreme Court Justice” and do not address the high possibility that this flow is not the result of any inherent superiority of the graduates of Ivies themselves, or even any superiority on their accomplishments or even education. How much of this is because the majority of people who accept applicants to Ivy Law Schools, the people who determine who will clerk for Supreme Court Justices, etc, are Ivy+ graduates themselves, and prefer the graduates of Ivy+ colleges?
There is also a long history of circular thinking: Ivy graduates are better so therefore we should place them in positions of influence and power. How do we know that Ivy+ graduates are better? Because they hold so many positions of influence and power.
PS. We can see the attitude of “an Ivy Degree indicates superior intellect, leadership talent, etc” on CC all the time. That is the entire basis of the “Ivy or Bust” mentality that we see in high school students and worse, their parents.