The idea behind the separation is that the government has the ability to make you do something with the threat of force. Not to say we shouldn't put protections from private corporations in place, but they can't legally imprison you.
The United States isn’t a democracy, it’s a democratic republic. Unfortunately, most of that was thrown out with the 17th amendment, and we’re paying for it now with increased federal control.
Don't turn your country into a prison on the hope that the warden will remain benevolent. There's no shortage of past and present examples of that suddenly changing.