Self preservation or self interest is important. You can't really do much for others if you dont have your own stuff together. Having said that, modern capitalism is moving toward pure self interest and even exploitation of others. The author correctly identified the one freedom the GPL denies - the freedom to exploit the work of others purely for your own gain.
Capitalism is not "about" anything really. It's a description that sometimes applies (if private individuals can own (and buy/sell) equity, and operate the means of production for profit) to economies.
Of course there are good and bad parts, of course there are good and bad implementations/representations/manifestations of such big concepts.
For example using a price system and voluntary exchange is usually a great way to get clear signals about what people want and value. But if the market is in a pathological state (monopoly, oligopoly, or monopsony, high barriers to entry, etc.), then the market becomes exploitative. Is this the systems's fault? Well, maybe, but it's not because people can own equity/machines, it's because that particular system/market is fucked due to various reasons. (Either due to historic reasons, eg. enormous income inequality led to a small clique of people owning all/most of capital coupled with a political system that wasn't able to represent the capitally-disadvantaged; or due to other failure of politics - eg. a group consolidated power into a totalitarian system which then dismantled competition.)
I'd say that a system whose essence is to concentrate capital in a few hands, and where concentrated capital provides the power to tilt the system in your favor, is very prone to ending being fucked up. It's not that other political doesn't also suffer from this problem, but capitalism is not exempt from it.
This question screams for some quantitative analysis. What's the model, then let's crunch the numbers. Otherwise I fear we get into a yes it is, no it's not, yes it's inherently that, no it's not inherently that.
What is the essence of capitalism? That private property protection extends to capital goods, they can be legally bundled up and sold and bought.
Does this have any inherent dynamic about concentration?
I don't see it.
Throughout our history we always had inequality. Maybe capitalism mirrors that. (Does it exacerbate it? I don't know. It usually allows for competition, which should force inefficient markets to turn into efficient ones - which would provide a niche for everybody, but of course there is nothing inherently there to guarantee this.)
So I have to agree with you, basic bitch capitalism is too vague and as such most of its implementations are bound to fail due to human nature.
Now, in capitalism, where exchanges can be influenced more by those who have more wealth to begin with, it's pretty obvious that it will naturally lead to extreme concentration of wealth. So I don't believe this question "screams for some quantitative analysis" but there you have it anyway.
The essence of capitalism is indeed the protection of private property and the resulting dynamics will lead to the aforementioned results. I don't know how you cannot see it.
As for inequality throughout history, it is actually a pretty recent phenomenon. Considering humans have been around for 100k+ years, and that we were all pretty equal up until around 6k years ago, inequality is very much an exception in history rather than a norm. And you can make a strong argument that inequality only really took place once humans became sedentary and started to implement a practice of private property.
This is also how I think about human nature. The "nature" of hoarding and greedily taking everything and leaving your fellow humans with barely enough to scrape by is not something we have always done. In fact, we only became so successful in nature originally due to our innate capacity for co-operation and our social behaviour and language. The fact that our "nature" for over 90% of our existence was very different to the brutality of capitalism that we see today goes to show that there is no fundamental "nature" that explains inequality. It is clearly a function of the current system rather than an inevitability resulting from the nature of its participants.
No, capitalism is about enriching yourself by, among other ways, providing others with products and services they want.
There's a slight but important difference between providing people what they want/need in exchange for money, vs. trying to make people give you maximum amount of money for minimum value provided. A lot of the problems attributed to capitalism are consequences of companies doing the latter rather than former. Instead of serving customers, they mine them. The current euphemism for that is "monetizing".
