I've never run a company so this may be naive or uninformed on my part, but I get the impression that hiring and firing people, at least here in California, can

I've never run a company so this may be naive or uninformed on my part, but I get the impression that hiring and firing people, at least here in California, can be a costly process with regards to unemployment insurance, litigation for wrongful termination, etc. Again, I may be overestimating this burden on businesses so please correct me if I'm wrong. One thing I've noticed over the years is that despite how good your interview/hiring process may be, you always end up with some hires that don't work out which lead me to believe that you probably turn away a near equal amount of applicants that would have been great employees. It's just very difficult to evaluate someone over the course of a few interviews. For entry level positions this is even harder since you may not have much professional experience or reputation to go by. I've always thought it would be interesting if companies would run a kind of tryout phase of employment, say 1-3 months, paid of course, at the end of which the top performers would be given permanent employment. This way a company might be willing to take on more marginal applicants with the knowledge that it will be very easy to terminate them. I'm sure there are negative aspects of such a system that I'm not considering, but as a person working in aerospace doing manufacturing/skilled labor and without any formal education beyond high school to fall back on, I always thought such a system might be a good way for someone like me to get their foot in the door.