You say that and I’ve seen several companies in practice echo what you’re saying. However, I fail to understand why they don’t simply make better use of contracts and probationary periods to solve that specific problem.
While I agree interviewing has gotten ridiculous with all the leetcoding and ten rounds of interviews and FAANG cargo-culting and whatnot, one small advantage - assuming I'm not desperate for a paycheck - is that it gives me, as a prospective employee, time to consider and withdraw my application if I see too many red flags or I just prefer the devil I know.
A short interview process with a probation period on the other hand is a big roll of the dice. Maybe I'm not able to ramp up on time, or make a silly mistake due to unfamiliarity with the codebase or underlying business logic. Maybe I don't get on with the team or manager. Maybe I'm going to be dumped into a doomed death march project on day 1. I could find myself unemployed a month later with an embarrassing gap in the resume. Perhaps on the other hand a better interview process (not longer, just have properly trained people and constantly improve the process with feedback) would save us all that pain.
Probationary periods could work but it's a coordination problem. Such periods are the norm in Europe (coz it's very hard to fire someone) but for an at-will place like the US, given that the industry doesn't really do probationary periods in general, any employer who starts doing it would be at a disadvantage.
In the sense of offering signing bonuses for term lengths that get repo’d if the contract length is broken.