1) My class had 30+% go into PhD programs, with over half of them receiving Fulbright/NSF/comparable prestigious research grants.
2) Earlier Olin classes graduated a larger percentage of people to take on high-paying jobs at Google/MS/IBM (and later FB/Twitter). It has shifted towards more academia and entrepreneurs
3) As one of (only) four international students in the first class (5% of the incoming class), yes, fewer international students. Yes, international students come from cultures less encouraging of entrepreneurship. While I'm definitely from one of those, being at Olin brought me around to entrepreneurship -- I wasn't interested until nearing graduation, reinforcing the article's point that Olin nurtures and graduates founders more effectively than other schools. I would almost certainly have worked a high-paying software dev job if I attended Stanford instead.
2. Olin is a great school. I doubt undergraduates from Olin are paid substantially differently from those at Stanford. There is probably data on this.
3. Seems the most likely explanation. Or just random chance.