Large corporations tend to hire and retain the wrong people (see the book "Snakes in Suits" by Industrial Psychologist Paul Babiak). The Human Resources departments are making errors in who they allow in to interview. If you do not have a network connection you are unlikely to get hired in a STEM profession, especially if you are female. In my case, ALL interviewers for every job were male. If you are not in your twenties and gorgeous you're less likely to be hired. Male co-workers have a difficult time allowing a female worker into their "club."