Not only does this disincentivize HR from running fake vacancies or stringing multiple candidates on just to keep their options open, but it also solves the problem of unemployed people job-searching effectively working full-time for free. The fact that companies would have to pay to hire workers would mean they try to make the selection as short and effective as possible.
Generally, my out of town interviews include paid airfare, hotel and meals to do the interview, this has been the professional standard since the 1970s and before… Yeah, it’s “unpaid time” but the expenses being borne by the company in the process are pretty obvious, and not insignificant.
Now, I can easily imagine today with AI HR screeners playing games of 20,000 questions before admitting you to a face-to-face round, yeah, that’s gotta be annoying. One way to win those games is not to play, only deal with companies that respect your time - I understand all too well that sometimes there aren’t any - but if they’re wasting your time like that during the interview process, odds are high that they don’t really have anything to offer anyway.
At more of a bottom-end job hunt, in high school I drove down the beach stopping in at every hotel filling out applications cold - low investment on my part. Four months later, I got a call back, apparently I was the only application on file.