So if after 7 months you suddenly realize that you've hired a bad worker, you're doing something wrong.
Being able to fire people easily is good for the business owner but bad for the employees. That's part of the reason unions exist and are useful.
This line of thinking has ruined the auto industry in the US and it's one of the the reasons we have a terrible education system.
If I have a bad worker (even after 7 months), I should be able to easily get rid of them (with cause). As a business owner, I shouldn't have to waste my time going to court or having some sort of 3rd party vote on whether I can fire them or not.
Businesses will never thrive in this sort of environment.
An employment market with too few workers (where it's easier to find a job) is good, but isn't enough if all the jobs require 14 hour days, working with deafening machinery with little to no safety equipment or training, for paltry wages.
Now, if we're honest, modern unions work for all of those things too, even if major unions are sometimes seen in less positive light sometimes.
What you really mean is that you want to be able to get rid of employees if you don't need them anymore or if you can find cheaper employees (for instance overseas).
That means more precarity, lower wages, less employment for women and older workers for instance. And don't tell me that it'd be easier to find a new job if you get fired and that everything evens out: most jobs flee towards developing countries these days, so it's not a zero-sum game.