Because it's a lot more predictable. Put in the necessary effort and you are almost guaranteed to get a FAANG job. And the best part, it's completely clear where that effort needs to be directed. Yes, you need to have the smarts, but for a business that pays as much you need to have a lot more than that, plus luck. I'm all for entrepreneurship and personally couldn't work for one of those companies, but with FAANG salaries being this high I don't think those people are making an irrational choice at all.