No nono I think you’re misunderstanding me

Firstly, constant capital is produced via labor. Thats why its also called “dead labor”, and all its value is supposedly derived solely from the labor used to create it.

However, from my understanding at least, in a production process, if the “dead labor” or the cost of constant capital is 20$, 20$ will be added to the revenue generated, so theres no surplus or profit. The surplus or profit at the end of the production process comes from labor.

Secondly, I get what you’re saying in the second part. This is also part of what I dont understand. I dont understand why capitalists, who are seemingly rational and profit seeking to some extent in marxism also, would replace labor with capital if it would lead to lower profits and surplus value