I would assume that a company without probationary periods is lower quality; either the work is so uniform that anyone can do it and employees are fungible, or

I would assume that a company without probationary periods is lower quality; either the work is so uniform that anyone can do it and employees are fungible, or they simply accept bad employees and live with them. Every company I've worked for has had some kind of probationary period. I don't live or work in the US, though; we can dismiss someone during their probationary period with ease, but after that they have workplace protections. If we could fire anyone at anytime for anything we like, that effectively makes the entire employment period a probationary period. Probation never ends if you can be fired at any time.