Because that is where he decided to work. I imagine he could find a role elsewhere focused on the areas you mentioned if he wished with those qualifications.
I don't doubt for a second that VCs fund a shedload of shite and that the social media world has pernicious effects that we are only just starting to understand, but in your example I don't think the tech industry can be blamed for your friend wasting his life building widgets.
Guess where I am in now? Machine learning consulting, left science - doing work that finally pays my bills and gets my kids to a first-class school.
However, I have observed friends seemingly get caught in a pattern: go to a top school, so you can have a high-paying job, so you can afford to send kids to a top school, so they can get high-paying jobs, so that...
In some folks' lives, the value of the "top school" seems to have a circular definition (not true for all folks, of course). It's a little sad, because by breaking out of that pattern, many more possibilities open up (like working in important and fascinating science for lower pay).
But yes, I totally understand what you are referring to - having my kids go to a private school means we have a number of those "circular types" you described to cope with...