I'm actually quite sure you'll find much more diversity from Stanford on that front.
CMU students tend to be a little clueless on the job search side of things, so they tend to stick to firms that are well known or well respected because they're safe.
I see no reason to go so far as to call the actual students in question "clueless" - but there is definitely serious bias in where certain companies do and don't hire. Apple recruits heavily from Stanford for CS, but recruits from MIT for ID, for instance. Some companies only look at MIT, or CMU, or Berkeley - or hire there "first", for no other reason than the founders might have gone there, and thus feel better equipped to evaluate the curriculums and students from those schools.
It's interesting to see where the top 1% of CMU kids go, but looking at the top 1% of every top CS school independently of each other would yield dramatically different results.
You're still in the broken zone. You went from CMU to Stanford. You're still thinking, "What are the big names doing?"
I'm legitimately wondering: how do you find the smartest, most ambitious people who never managed to get a big, prestigious name or title associated with themselves, and fix that?
CMU students tend to be a little clueless on the job search side of things, so they tend to stick to firms that are well known or well respected because they're safe.