I think your misconception, (and it is the misconception of many) is that the current American economy is an accurate representation of capitalism. It is actually corporatism. Big business fills the pockets of the politicians while the politicians enact legislation to protect the big businesses. You touched on this a bit with your windows/highway example, but it seems like you still view this as capitalism. I view this as one of the great deceptions that progressives have been able to impart on the people.

I also think that your characterization of the NAP is incorrect. I do not view it as the same line of thinking as marxism. Marxism ignores the fact that individuals are greedy and are interested in gaining wealth and resources. It discourages that human nature with no recourse for those who are discouraged. Contrarily, with regards to the NAP, while humans are also violent and the NAP advocates against the initiation of violence, it does not discourage the use of violence if attacked, thus offering a method of recourse to the attacked.

Lastly, I'm not blaming Keynes for bricks through the window. He didn't throw the brick nor pay anyone else to. Keynes did encourage "busy work" types of labor funded by government when there weren't enough productive jobs as a method of maintaining a flow of money within the economy. I don't agree with his opinion, mainly because once a government creates a job, no matter how useless it is, it is almost impossible to get rid of, so there a permanently pointless job sucking tax dollars from the people.