Capitalists do sell their labour, but they also serve the important fu action of BUYING your labour. If you want to sell your labour you need someone to buy it. Employers are customers
You are by the looks of it deliberately ignorant. You are not correct at all, all that shit is just capitalist propaganda.
These things are then sold to customers. A building is a good example. A capitalistspays for contractors. Contractors pay for labourers. A customer buys the finished building.
That is not how things work. Not many people make complete things themselves. Instead people sell their labour to a capitalist. The labour is coordinated to make finished things.
You just dont get it. Capitalist is nothing but a middleman, same as banks, as ll they really do is extract wealth created by others. There is absolutely no need to have such systems.
Actually they are important middlemen. They coordinate which labour to buy to create the finished product. Modern things dont get built without a lot of coordination.