No, because business and employees are not in equal barguaining position. Business always have an advantage and in unregulated markets they are more than happy to take advantage of their power position.
On the other hand, you can see these regulations as a collective bargaining between employees and business. Individual employees have no negotiating power against any corporation, but they all together can elect a government that will have an upper hand there, so it's just market behaviours.
And no, what you said about 20 hours work week doesn't work like that. I believe that many employers would be happy to pay only 20 effective hours a week for a software engineers, but sorry, my workday consist of some time needed to concentrate, get in the flow, release some stress, let the brain work in the hammock time, and you also need to pay for this, since you won't get these effective 20 hours a week without these other 20 hours. It just doesn't work like that. Maybe I would agree to be paid only for 20 effective hours a week, but my rate in that case will easily go double.
On the other hand, you can see these regulations as a collective bargaining between employees and business. Individual employees have no negotiating power against any corporation, but they all together can elect a government that will have an upper hand there, so it's just market behaviours.
And no, what you said about 20 hours work week doesn't work like that. I believe that many employers would be happy to pay only 20 effective hours a week for a software engineers, but sorry, my workday consist of some time needed to concentrate, get in the flow, release some stress, let the brain work in the hammock time, and you also need to pay for this, since you won't get these effective 20 hours a week without these other 20 hours. It just doesn't work like that. Maybe I would agree to be paid only for 20 effective hours a week, but my rate in that case will easily go double.