I don't have definitive numbers, but I'd say the vast majority of Marxists and the like are evolutionists (regardless if they're atheist, Christian, or other.) As one of the laws of evolution is survival of the fittest, this may draw some questioning as a contradiction. Indeed, it many propose that capitalism embodies survival of the fittest, with the CEO and board of directors being the fittest. They fought (and/or (il)legally exploited) their way to the top of the pyramid. Thus, they deserve to survive, or get their profit. But what if that's wrong?
Indeed, if only the CEOs survive they will have nobody to work for them or to buy their products and services. Therefore instead of capitalism being the embodiment of evolutionary thought, I'd posit that socialism is much more in line. The fittest is actually the masses, the working class upon whose back society rests. When the masses thrive, society itself does. Seeing the world disconnected and individualistically (or even broader as nuclear) leads to it's demise. However if we recognize we are all in this together, then we become the fittest.
To elaborate, with our current system the CEO and/or board of directors (or whoever heads the business, henceforth CEO, regardless actual title) make the majority of decisions. The workers do not determine their pay, how to use profits, tool upgrades, or most importantly, job security. This goes for entry level on up, until you get to the CEO. While management and others have a hand in raises or other parts of the business, if the CEO decides to axe one department or freeze wages, there is little recourse. For the CEO, the bottom line is profit and doing whatever is “necessary” to obtain it. This includes producing cheaper quality products for the same price, paying workers less (or stagnant wages), outsourcing, to name a few. The point is simple, profit over people, even if that means those people cannot survive. While the CEO may survive, it is temporary.
If we were to shift to the Worker's Self-Directing Enterprises, the workers take the place of the CEO. As such, they all, whether as a small business of 10 or large corporation of thousands, democratically determine the direction of the business. Is there a more efficient production process? Discuss, vote, and implement. Do wages need to increase? Discuss, vote, and implement. While I am simplifying the process for brevity, the list can go on. The method, which is meant to involve the whole workforce, has another fundamental difference: it has an almost guaranteed focus of people over profit. Rather than decisions being made regardless of the impact on the proletariat or planet, WSDEs make choices to benefit the worker and allow their communities to thrive. As we see ghost towns of former economic centers left crumbling in the aftermath of capitalism, we can see thriving and even simple surviving is not something that is possible in the long term for the current economic structure.