TDD is just one of many options. Personally I rapidly have LLMs rewrite code over and over until it is super easy for me to understand and exactly what I want, and then I generate tests to prevent regressions.

Regardless, I run a security auditing company where we constantly find severe bugs in human written code proving the engineers writing it had major gaps in their understanding of their own code. And, others have found flaws like that in my own hand written code! We humans are often very blind at seeing the flaws in our own logic and AIs learned from us.

Also, as code reviewers that can spot bugs authors and AIs miss, we are often paid a lot more than the original authors for our time. Also it almost never takes as much time as writing the code in the first place which likely required many round trips with customers to establish needs and fix bugs etc.

Your claims imply that only someone that hand types every semicolon is capable of understanding the code does not hold up even in the pre AI world.

Code review was the most important job in software engineering before AI and that is still true now.