I strongly agree with this analysis. It's already a population with strong STEM abilities, it should suffer from some sort of diminishing returns after an already high hiring standard on a company well-known for hiring only top students.

It's like conducting an analysis on skills of all F-1 drivers, and what differentiates champions from remaining pilots. I'd expect a lot of mindset-related and soft skills to appear as key indicators, and "driving abilities" to have a minimal gap between drivers.