Typically there's a lot of onboarding, and even a good candidate might not get a lot done in the first month or three... By the time you realize the new hire isn't a good fit, you've spent a ton of time on training.

Otoh, if you hire me to frame a house, it'll be objectively clear you need to get rid of me in the first hour, if not the first ten minutes. I don't know how I'd get past a screening for that either, but still.