If you already know _exactly_ what your code needs to do, you can "just implement it".
I find TDD to be very helpful in the cases where I do _not_ know everything in advance, because it lets me take small steps to explore things and I get very fast feedback if I "misstepped".
All of the methods mentioned are based on a reasonable core. It muddles the waters and make the snake oil marketing - the "this is the cure to it all" discourse - harder to dismiss. Testing is good. Planning is good. Discussing the project is good. But these things are beside the point of op. The point is, these cargo cults are designed to make consultants money. Now they have a lot of inertia because people grow up on it.
It seems like the new generation of software development silver bullets is "microservice", cloud "devops" etc... Managed kubernetes is not a bad thing. Configuration files, software defined infrastructure, etc, not bad things at all. But there is a definite market push in consulting for overtly complicated frameworks as The Way and people who are anxious about their complicated projects gobble it up.
