That's optional, for folks who WANT to commute (eg, either want a big house in BFE, or want to live the city life, or whatever). If you want a short commute, it's yours -- if you live in the city, work for one of the many tech companies up there. If you want to work at FB, come be my neighbor and walk to work, I live in a great walkable neighborhood <2mi from FBHQ.