Even given that data, he could still be stronger than the people laid off. Also keep in mind that there's some degree of luck involved in the interview process, and this plays an especially large role when you're looking at a sample size of 1 person.

True. He could've definitely been a one-off false positive.

If you're a rockstar, why would you go to Yahoo when you could have real infrastructure to work with at Google or Facebook? You'd rather be job hunting in 12-18 months when Yahoo tries again to figure out what it wants to do?

Maybe you get a chance to build real infrastructure at Yahoo, instead of having to be a small cog in one that's already built-out.