Capitalists stay rich and keep getting richer because of how the M-C-M cycle works. Before capitalism, people like farmers would sell something to get money, then use that money to buy what they needed and sell. Money was just a step in between. Capitalists do it backwards. They start with money, use it to buy something, then sell it to get money back. But money is never supposed to be the same, it has to be more. That extra bit of money is the profit. So where does that extra money come from? Capitalists pay workers a wage, but that wage only covers enough to keep the worker to have food, rent, stuff like that. Let’s say that wage only really covers about 4 hours of the workday, but they work the full 8hours. Those extra hours, the worker is still making stuff and creating value, but they’re not getting paid for that part. The capitalist just keeps that as profits.And this is why the wealth never stops growing. Once the capitalist has that extra money,they put it right back buy more materials, hire more workers, make more products, sell for even more money. It just keeps repeating and growing every time.