Times have changed , before the advent of capitalism artisan and peasants would have small-scale commodity production meaning C-M-C . The same value that the (C) has in the beginning is the same value it has at the end.At this time the surplus value wasn’t in the picture;it was more about exchanging money for a personal need like food or clothes and vise-versa. 

The difference between Small-scale commodity production (C-M-C) and buying in order to sell(M-C-M’) is the( M’ ) because the value grows meaning the same money that was invested or profit in the beginning has grown.In the other hand (C-M-C) the value stays the same from where it starts .

Capitalists remain wealthy because they use what is called “we need money to make money” meaning that with a percentage of their surplus value they use it for another investment as buying to sell to keep the money in circulation.(M-C-M’) is mentioned as the general formula of capital because the money that is being used for the commodity or produce is the same money you get after it’s sold but at a bigger rate meaning you get way more money of what you spent to buy the commodity.

Labor power is basically the mental and physical capability to be a human and when you get a job as a working-class you’re selling your labor power for a wage or salary.Capitalist use the first M to buy the labor power of many workers and also to buy the means of production to help the workers function. C is the result that workers give after selling their labor power in exchange for a wage or salary . M’ or M plus is the final profit that is privately owned by the capitalist .

Capitalism emphasizes workers exploitation and little to no compassion because if they were to be reasonable towards their workers capitalist wouldn’t have a surplus value or no money left over due to the fact that capitalist also need to pay means of production like materials , machines ,or as simple as paying rent for the location.

In conclusion, capitalists maintain and increase their wealth by exploiting their workers . Increasing their relative surplus value is what keeps capitalists in business.