Well I went to a major feeder school and know a lot of people hired by JS.
The class of people hired by firms like Goldman Sachs is obviously nepotistic in nature and very different from the class that JS hires.
A substantial portion of the GS mix is athletes & what I would call traditional Northeast elites, Jane St hired mostly out of the top physics, CS & applied math classes I was in.
Beyond that, having parents who are prominent professors is nothing special at these schools and definitely would not give you pull at these institutions. Finally, Jane St has no incentive to engage in this sort of hiring because they are not customer/client facing.
Hahahah its the funniest thing I ever read. Some people are so doggedly invested in the believing myth of meritocracy. Yeah right a private firms hiring is totally meritocratic.
Cultivating relationships with influential people makes sense for an investment bank. Jane Street is a market maker, what exactly would they gain from it?
I promise you I have no affiliations with JS whatsoever, just think that there is lots of sloppy reasoning going on in this thread.