[ElProlactin]

If the cost of hiring the wrong person is huge, the cost (in terms of time and money) of conducting on-site interviews is almost certainly lower.

Also, in terms of the costs to the applicants, this touches on the oligopolistic nature of so many industries today, which has resulted in high concentrations of the most desirable jobs in places with the highest costs of living.

Basically, unless you already have a FAANG job or are independently wealthy, it's not easy to up and move to Silicon Valley, Seattle, etc. and job hunt.