This argument assumes that code is an ends not a mean, which is false. The value you deliver is not your code, it’s the enablement of business functions. Let’s say you launch a new product that gains traction. Sure, in 5 years your code may be refactored out of existence. But the people doing the refactoring only have jobs because of the value you delivered when launching the initial product. That is your lasting contribution, not the lines of code you wrote.