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.
OK, but who does it cost more? The person being interviewed is also burning opportunity and time but we assume it’s free because no one is paying them?
Sounds like it wastes both sides’ time and money, but measuring up to determine who is wasting the most time and money doesn’t really help anything other than furthering Whataboutisms.
Ideally, we change to a system that doesn’t do that (nearly as much).