For an academic, you seem incredibly incapable of parsing a simple sentence.Your 'rant' appears convincing, superficially, though you are clearly not an academic nor studied in Marxism/economic history.
'Class struggle' is indeed the basis of his analysis but by no accident; it stands as the most all-encompassing means of identifying and explaining social and economic organization over time.
What Marx demonstrated (using that framework), is that, unlike earlier forms of social/economic organization (hunter/gatherer societies, feudalism/manorialism), 'capitalism' was not part of a natural evolution, but a system opportunistically put into place by a dominant class at the demise of feudalism. In no system prior to capitalism, did an unequal exchange of labour for wages exist; nor was social/economic activity predicated solely on profit. Under the previous system of economic organization, both a lord and his serf benefitted from a more equal, mutually-beneficial exchange in which serfs were rewarded for the products of their labour, in kind.
And that is where most people miss the point. There is nothing inherently 'natural' about capitalism; it is merely a system put into place by a ruling class who seized an opportunity to do so, and propped up by system of (non-economic) institutions intended to preserve the position of that ruling class.
At no point did I say that capitalism is "natural". I said that it took advantage/used human nature, which isn't the same thing as natural and as anyone who had the simplest grasp of the English language would have understood.
Capitalism uses human nature. It doesn't sugarcoat reality the way socialism/Marxism do. It doesn't pretend it's your friend, or that it's your buddy, or that it's looking out for you. It doesn't promise you, as socialism/Marxism does, that if you're a stupid, pathetic, lazy loser that you'll be able to get by.
Is capitalism set up to benefit the powerful and the ruling class? Yes. But so is, in the end, socialism/Marxism, because when you add human nature into the game, you always end up with a ruling class in THAT system, too. If anything, capitalism allows for a regular churning of those in power at the top, as if they're not smart enough to keep their positions and their power they'll lose it to the entrepreneurial among us.
Your "yeah, but everything devolves into class warfare" is a very typical myopic response that is woefully narrow and closed-minded in its viewpoint. That's the laughable thing about liberals: you enjoy preaching open-mindedness and a wider worldview, but in the end your point of view is just as narrow as the worst bigots.