In fourth year HS, we had an Economics subject, and back then I was fascinated with the idea of free market capitalism -- the free market, the invisible hand, the law of supply and demand, and the idea that through competition we are forced to adapt and become better and more efficient in order to survive. Capitalism mirrored the law of nature: the strong will survive.
These days, I am much less enamored with the idea of capitalism. Not that I disbelieve that it makes us more efficient, but that ruthless efficiency has a cost. Like the law of nature that it mirrors, capitalism ensures that the strong survive, but the corollary is also true: the weak will die and be consumed by the strong. Humans are a societal species, which means we are supposed to be stronger together. But capitalism, optimized towards the pursuit of profit, often times can force us to sacrifice the greater good in favor of individual interests. Corporations especially, will often act as soulless entities whose mandate is above all to pursue profits in the name of the stockholders.
Many of the societal ills in the world today can be directly traced to the ruthless efficiency in pursuit of profit, the prime example being environmental issues like climate change and pollution: governments don't want to enact stronger controls because it will cut into corporations' bottom lines, and politicians don't want to piss off corporations that they rely on for donations. Capitalism's ruthless efficiency has brought us to a world of wage inequality, banks too large to fail, and large monolithic companies that are virtual monopolies due to network effect. It's a system that reinforces the rich and powerful (the strong survive) while the masses suffer in silence (the weak will die)
The emergence of large monolithic corporations wielding monopoly powers is especially challenging, and is a natural consequence of "the strong survive". As the rich get richer, they can use the accumulated power and money to defeat any further competition that dares to challenge them. Thus they are able to resist becoming more efficient in favor of simply using their leadership status as a blunt instrument. You can see this in the tech industry with virtual monopolies such as Google (search), Facebook (social networking), Amazon (sales, cloud hosting); realistically they can only be challenged by companies of similar scale, there is no space for smaller guys to move into.
I still think capitalism can be a force for good, and that efficiency is still something to strive for. But I also now believe that this efficiency should be tempered by a corresponding collectivism, whether enforced by states (through regulation or subsidies or welfare programs) or by some other mechanism. The idea of something like universal basic income is promising, but under a purely free market system, I don't see how it could work. It is hopefully not too late for us to find a way to navigate our society to a post-scarcity Star Trek-like future, where humans are able to dedicate themselves to scientific and artistic pursuits without worrying about survival.
(If this sounds like a rant with no proposed answers, it is. This post and others like are just me sounding off on how my thinking and philosophical leanings have changed throughout the years, so that I may consider where it can lead me to. Feel free to debate me in the comments.)