It's reasonable to imagine that there was some sort of "natural selection" of economic systems and that the one that emerged is relatively close to ideal.

That doesn't follow: the crucial thing about natural selection is that, given path-dependence and local optima, it doesn't matter which particular feature causes the "fitness"; only the fact of its total fitness matters, and any given feature could just be a "hanger-on".

Now, if you had numerous worlds (or merely societies) to compare, and a rigorous, well-accpeted definition of what counts as capitalism, and strong selection pressures and "mutuation", then the present content of a system would be strong evidence of the superiority of all of its parts. But that's not the case.

I'm open to suggestions for how I might improve the introduction to the article to make the article more palatable.

You should have dropped the whole pro-capitalist cheerleading and simply discussed the belief that jobs are zero-sum, the evidence that people generally hold this belief, and its errors. (And then discussed how people can be made to change this belief, given their general cognitive structure.)

I'm open to suggestions for how I might improve the introduction to the article to make the article more palatable.

I was going to suggest this, but I see you've already added it: thanks for editing in your definition of capitalism at the top of the post. When I first read the post, that was something I thought would improve it. Like SilasBarta I thought it was a bad idea to leave unclear what you were counting as capitalism.