In every area, the best (and sometimes only) jobs go to the best people. Where an applicant attended college can have a big influence on how they're perceived by prospective employers.[0]
The question of individual performance also comes in to play. Some reports have said that almost 75% of STEM graduates don't actually work in STEM.[1] I'm sure some of that is driven by the fact that companies want to hire above-average people - but only 50% of people fall into that category. Even in the current crazy environment in computing, there are computing graduates who can't find jobs.
There's a lot more to this issue than engineering vs. art history.[2] Sure, there's a lot of people who get degrees in fields with small labor markets. There's also the 50% of graduates with below-average transcripts. On top of that, there's people who think attending a lousy college is better than no college at all - they're shouldering a whole lot of debt for something that may ultimately bring them close to zero benefit.
There are a lot of people for whom college has paid off in spades. These people aren't necessarily lucky, they may have simply made more sensible choices.
[0] Of course there are pros and cons to this, but we know it's true.
[1] http://www.cbsnews.com/news/a-shortage-of-scientists-and-tec...
[2] I'd rather an art history degree from a great school than an engineering degree from a terrible school.