> the cost of a mishire is huge.

Absolutely agree and I'll add that you're shopping in a market for lemons. There are multiple adverse selection criteria against the pool of job seekers. (Excellent engineers are more likely to be retained/less likely to be fired. Excellent engineers are more likely to receive an offer when they do interview. Poor engineers are less likely to be retained, more likely to be fired, less likely to be hired.)

In steady state, the applicant pool is of lower overall average quality than the pool of employed engineers.