the original "No True Scottsman". There really is no way for it to exist. Sooner or later inheritance alone means somebody is going to get advantages, use them, and start locking down wealth. As soon as you introduce anti trust law you've busted the system.
Private power companies don't work because they don't add value. Power is something _everyone_ wants. When everyone wants something it makes sense for it to be run as a public utility. Adding a private element just lets someone skim 10-20% off the top is all while they cut down on safety. Anyone who thinks private companies are inherently more efficient needs to go watch Office Space again and then go check out the (rather amazing) American Postal System or look at a well funded DMV (as opposed to a DMV run for the purposes of triggering knee jerk reactions from anti-gov't types).
Sure, you have to keep an eye on what the gov't does, but we've already established we have to do the same with business (see the aforementioned anti-trust laws). That's the trouble with socialism. Free Market Capitalism claims to have principles and easy answers. That they're the wrong answers isn't really the issue. Socialists basically say: Hey, the world is _fsckin'_ complex and it takes real hard work to make things run smoothly, and then a Socialist will start blathering on about all the things you need to do to make a system work.
The way I see Free Market Capitalism is this: When have you ever had a difficult problem that got better by leaving it the fsck alone?