...really, we've not really incorporated it into our understanding of the natural world, either. The closest we got was the late 19th century project to justify the racism we were already doing (or "Social Darwinism", when it's attempting to appear grown-up and respectable).
The way we talk about class is still firmly grounded in 18th and 17th century ideas. An evolutionary perspective would have us thinking about this along multiple generations, across enough spans of time that the individual is incidental - a part contributing to a greater system. On this scale, it doesn't matter how good, how just, how longsighted this or that president or industry titan or """great man""" is, cus soon they'll be dead. Someone else moves in to take their position. It's the structure around them that truly continues, that defines the flow of history.
That kind of thinking is anathema to the US civic tradition. We are discouraged - in schools, in churches, on television, in our art - from such broad considerations. It doesn't matter that statistically most people here die in debt having worked all their lives -- they just didn't do enough willpower! So they must deserve their sorry plight! The Elect, whether chosen by God or the Market (not much of a distinction, for a lot of people here...), are thus equally deserving of their 'success'.
Even our atheists think like this! They've just replaced 'God' with an Operating System. They belittle religion for projecting a familiar patriarchal figure into the great unknowns of the cosmos, then turn around, point to the sky, and say it must be a desktop interface. And non of the underlying assumptions change! The aesthetics and the words are different, but we're still trying to cram a planetary biosphere of billions of people down the throat of a framework that refuses to consider anything bigger than the individual!
You might be interested in reading Greg Grandin’s The End of the Myth. It gets into both the history and collective psychology of the frontier and how that creates a vision of capitalism as not evolving, as you put it. Essentially, having an “untapped” frontier always out there meant there was a “release valve” on the American economy and society, always a place where capitalism was in the primordial stage. Thus, the sort of pressures that evolve capitalism to latter stages weren’t present for centuries. Even once the actual frontier ran out, the mentality of it being there persisted, with the assumption that there must be alternative frontiers out there to be settled (the phrase “digital frontier” got bandied about a lot in the 90’s and early aughts to describe the Internet).
