Google hires their permanent staff straight from the two dozen or so most elite universities in the US and in other countries where Google has a major presence. It appears very rare that that these employees, including the minuscule percentage who are African American or Hispanic, are the first in their families to attend college. They arrive at the Mountain view campus driving the kind of cars that affluent suburban parents buy their children upon graduation from high school. After the second or third bonus check they transition to a new car, often a Prius, Volt or Leaf.
Full time staff who want to work in other countries usually work in their home country for a couple of years before transferring to one of the major facilities in Mountain View, Dublin or Hyderabad where they can eat lobster for lunch and work with managers who help guide them toward success. Full time staff who demonstrate less success are usually guided to out of the way positions in Adwords/Adsence sales groups or are shuffled off to something called "people ops" which seems to have to do with providing balloons on staff birthdays and making sure everyone has their full allocation of office supplies. Few people are every fired from Google but a lot of people get the message that it's time to leave.
As for contractors, they get free lunch and a steady paycheck. Contractors are generally speaking more ethnically diverse than full time staff. In the US, whites perform administrative and network support functions, gays hold down the reception positions, African Americans work in security and Hispanics in food services. See, Diversity!
I met exactly 2 people in several years as a contractor at Google who made the transition to full time employee. One was an NYU grad, the other from Humbolt University Berlin - both schools that Google recruits from. No community college grads. Contractors live a somewhat Nietzschean existence. You are very much untermensch and Google has no interest in developing you for anything other than the narrow niche that you were hired for.
Fascinating insights from personal experience! Thank you!