I think there are benefits to us all having breaks at the same time, so we can see friend and family. I think we can survive without everything being available every day of the week.
Public service announcement: that line of reasoning makes you a social authoritarian. You want to tell people when they can and can't go to work because you know what's best for their social life.
The problem I see is that your kids are in school the week... And you should have at least one day with your kids (society benefits a lot of this, and it makes day care cheaper) . Maybe have either Saturday or Sunday of mandated free time, and then Amazon could hire people either Sunday or Saturday...
Perhaps people with kids are best off if they look for jobs where they can spend the weekend with their kids. But not everyone has kids - some people are busy during the week with, say, university, and might welcome the chance to make a bit of money on the weekend.
Fortunately, here in Italy, Mario Monti got rid of some of the rules about working on Sunday.
But it took France until 2008 to stop sending kids to school on Saturday mornings while the parents were home, so obviously you coped without a complete overlap of leisure time among the family for a while :)
It is impossible to mandate that nobody work on any of the 7 days, because hospitals. So we already admit that some people will be working when most people are not - the question is whether we tell them to suck it up, society is going to ignore them forever, or whether we can re-arrange society so that the family of the ER doctor can also work Sunday and take Wednesday off to be together.
