I suspect that most of the young tech and finance workers in NYC live in Manhattan, Brooklyn, Queens (LIC in particular), Jersey City, and Hoboken -- all of which are expensive and right in the center of the metropolitan region. I am sure some recent college graduates are commuting from the suburbs but for the most part suburban life attracts people who are more established in their careers (and who are not planning to stay out late enough that the late night LIRR/MNR/NJT schedules are a consideration).