"However, the act of writing tests first has a powerful benefit: the code you write _must_ be testable. It is hard to understate this benefit. If forces a level of decoupling that most programmers, even very experience programmers, would not otherwise engage in".

I'm sorry but I really find that sentiment to be totally inaccurate. I've never seen a good experienced programmer write hard-to-test or coupled code, regardless of whether they are using TDD or not. A hallmark of when makes them good is that they all have some testing methodology that enforces this and works for them. TDD is one, but there are many others (and yes, that includes good manual-only testing).

I also don't see why you believe TDD is the only way to successfully refactor code, or that only developers who use TDD continually refactor their code to eliminate technical debt and increase productivity. Again, every good programmer does this. TDD is one way to get there. It is not the only way.