The capitalist class, known as the bourgeoisie, derive profit off of the labor of the proletariat (the working class - that's us!). This is usually done through ownership of private property.
The modern bourgeoisie is made up mostly of investors and landlords.
In modern capitalist society, it's rare for one owner of a business to own the means of production. These days businesses are largely owned by shareholders.
Owning a share is owning a part of a business. It can be bought on a market, and gives those who hold at least 3%1 of a company's stock for three years the right to nominate candidates to executive boards, who make decisions on behalf of the shareholders.
The company itself, however, is comprised of workers. These workers are the proletariat. They are essential to keep the company running because they are doing the necessary work to provide goods or services to be distributed. Without the workers, there would be no company.
These workers do not have a say in how the company should be run. Some companies might offer shares to their workers, but you won't find any offering anything close to 3% or more in total shares. This is how money and power end up in the pockets of billionaires.
Even worse, despite only 3% of Amazon being worth $47 billion dollars, the company has a history of abusing its workers with low pay and harsh work conditions. Is it possible that if large corporations paid their workers more, the shareholders might not be making billions?
Landlords profit by owning property that they indefinitely rent to tenants2 Many have made a career of buying homes and renting them out, in the interest of earning money with minimal effort and time spent.
One who takes out a mortgage on a house often rents that house to tenants and charge more than the mortgage is worth, which results in an unnecessary overpayment that goes directly into the landlord's pockets.
When the mortgage is finally paid off, the landlord's profit margin widens since there are no more payments required to offset the cost of maintaining the property.
The reality is, the people paying for that mortgage are the tenants. Once the tenants have paid the mortgage in full, they are not entitled to the house. They are, however, entitled to continue renting - unless the landlord decides to vacate the property. Tenants who work to pay their rent, therefore, are also the proletariat.
Neither of these ways of earning income contribute to society in any meaningful way. In fact, they do the opposite by exploiting the workers who do.
The bourgeoisie class has made it clear that it thinks people who don't work are lazy, but they do not work themselves. They think social programs discourage people from wanting to contribute to society in a meaningful way.
The ability to "become" a successful landlord or investor is dependent on having money to begin with. The capitalist system enables the people with the most ability to improve society (billionaires) to contribute the least amount to society?
Both investors and landlords profit off of the hard work of other people. They do this by paying as little as possible in wages, and requiring as much as possible in rent. The existence of the bourgeoisie depends on the proletariat, which means the workers (that's us!) hold the power to potentially bring capitalist class ownership to an end.