" Good companies grow and need more employees."

Yes. But it is incredibly hard to get into a good company.

"and let me also say that if the market for lemons accurately describes the labor market, why is it that tech is the only industry with such broken hiring practices? "

In other "tech" industries it is the same. How do you get into a blue chip company?

1. contacts of your parents

2. contacts of your professor at University

3. you work for a start-up that they buy

In my experience this is true for 9/10 people I know.

I did my PhD in NYC and I once was asked in an interview for a med-sized medical company what the street name in Brooklyn is with all the hipsters. Think deeply what could be the reason for such a question.