The modern economy is founded on cooperation. Take this video which describes how the Apollo rockets to the moon were created by the labour of individuals at twenty thousand firms, government agencies and universities:

https://www.youtube.com/watch?v=9dXdDXX4QFA&t=508s

In a similar vein, most of our current standard of living is a free gift of the technological system and those who came before.

Individualism, in the sense of the economics textbook's feral atomism, is a myth. Which is not of course to condemn true individualism, which basically means standing up for what is right no matter how unpopular or dangerous that might be, but which has very little to do with the celebration of predatory and sociopathic economic ideas.