How to Criticize Capitalism
Capitalism is all about capital, it's about what society lets you do when you own things. When you own very big things, like a factory, or a mine, or a lot of farmland, a capitalist society allows you to hire people to plow your fields, to dig your mine, and to work your machines. You hire people to exploit your capital. The people working in your factory agree to work for some wage, and you sell what they produce for a profit. The money you make selling what the workers produce must be greater than the money you pay them in order to turn that profit. Even though you didn't actually make the product, your contract with the worker allows you to capture the value created by their work. To me, there are three things that define a capitalist society, you can own capital, you can hire people to use that capital, and you are entitled to everything produced using that capital.
The Fundamental Power Structure
In a capitalist society, you have owners, and you have employees. Now, imagine a village inhabited by a wealthy family who owns a large farm. They hire people in the community to work on their farm for a wage. They are the largest farm in the region, and let's say they are also the most efficient. This means that they are making the biggest profit, and their wealth growth is outpacing the surrounding farms. They have some competitors, but they're already ahead and want the best talent, so they pay their workers slightly above what their competitors offer. Eventually, the family decides to reinvest their farm's profit by buying up smaller farms.
From the perspective of the worker, their options over employers quickly dwindle. Acting in their best interests, the family will decide to slowly lower the wages of the workers until they notice workers leaving for other villages. The family is operating a monopoly on agriculture in the village. This monopoly drives down wages over time, while the economic output (amount of food grown and exported) might have simultaneously increased.
The family who owns the farm also own all the food grown on that farm. This fact of ownership is reinforced by the government through the hiring contracts with the workers, and with the family's property rights over the farm. Who owns the farm is what fundamentally defines the power imbalance between the family and the farm workers. The better the farm does, the better the family does. Critically, the performance of the farm doesn't necessarily have any relationship on the economic wellbeing of the workers.
As the farm grows larger and more efficient, these gains get concentrated into proportionally fewer hands. As the family becomes richer, and gains more control over farmland, they gain more control over the local food economy. This means they can decide what crops are available to people, who is allowed to buy the crops they produce, etc. They translate their economic power into something that is almost indistinguishable from political power. This political power, created through their domination of the market, gives them more levers to increase the scale of their business. Which propels more growth, and definitionally more inequality.
Capitalism, defined by right to own, right to hire, and right to capture, has the fundamental property of inequality baked in. And by its structure, economic growth will translate into increased inequality, holding all else equal. Notice that the fundamental property of capitalism is not a market, its an ownership structure which prioritizes concentrating wealth into the hands of those who already have it. The market just exists as something that can be harnessed in service of the power structure.
Markets aren't a problem, but they aren't a solution
All capitalist economies have monopolies and oligopolies. Most sectors in capitalist economies are dominated by a handful of companies. Some companies dominate across multiple sectors. Which companies dominate each sector changes over time, new competitors arise, and innovation disrupts existing leaders. But the basic fact remains that most econommic sectors remain relatively concentrated. This naturally implies economic inequality given a capitalist ownership structure. Few companies means a handful of wealthy owners, and reduced wage competition.
Even as companies compete, and the overall economy grows, concentration does not tend to shrink. In some cases, technological advancement increases market concentration, since a single highly innovative company can quickly dominate an entire sector. Markets can never solve this inequality because markets didn't cause this inequality, the ownership structure is solely responsible.
Solving the problem
The fundamental issue with capitalism is that it freely permits unchecked concentration of wealth and power within private entities. Those who are wealthy are legally entitled to leverage the economy to increase their wealth. This creates an economic system which is fundamentally powered by inequality. At its core capitalism is an ownership model.
Unfortunately, exactly what ownership model should be adopted to replace capitalism is an extremely challenging question. Systems which distribute power are always more complicated than those which concentrate it. There are many successful models out there for how collective ownership can work, coops are one example. Permitting a capitalist ownership model for small companies but then requiring them transition to sharing equity amongst employees once they reach a certain size is another option. To me, a post-capitalist society is one which actively works to design policy and laws to deter power from concentrating, while carefully designing incentives around which the economy can organize.
Post-capitalist societies are those which could leverage markets more effectively than capitalist ones. Large megacorps become slow and inefficient as they scale in size, making them unable to handle disruptive competitors. Large corporations, which must enforce a hierarchical management structure to preserve ownership, are not too dissimilar from communist central planners. Large companies often become overwhelemed with bureaucracy as they scale. Collective ownership models are unburdened with inefficient hierarchies. They can organize into hierarchies when needed, and can distribute themselves horizontally to attack problems in parallel as necessary. Organizing collectives is hard, but companies which organize horizontally have the capacity to be vastly more efficient than those which cling to hierarchies and ownership. Valve software is an interesting case study for some of these principles. The economic growth of democratic societies versus monarchical socieities is another interesting case study.
Post capitalist socities still have competition, they still have companies. People are still greedy and want to get rich. Companies still work to maximize their profits. But, when they succeed and get rich, those who helped build the company own what they built. There will still be economic inequality, but this inequality is not going to span orders of magnitude.
Dreaming past capitalism means dreaming past how we understand ownership. It means abandoning the notion that wealth entitles us to use the labor of others to enrich ourselves. Much like democracy was developed to end the tyranny of kings, collective ownership must be developed to end the concentration of economic power. Restructuring how ownership works is not easy, democracy wasn't easy either. The simplicity of a monarchy is much easier to reason about than the immense complexity of a modern democracy. But, few people would ever consider going back.