I've seen startup devs who couldn't cope with changing requirements fast enough. There was just too many moving parts at the same time.
Hell, I've been one of those devs! Great code is the exception, not the norm.
When I learned TDD, it greatly improved the quality of my code. If TDD is a bottleneck for you, maybe you need to learn to touch type.
My 2 cents.
TDD is one of the few actual disciplines I know of around coding that can't be just glossed over or faked. One either does or does not. This is doubly true in a pair programming environment. Not using one of the established patterns? One can argue around that. Not doing TDD? Justification usually has to tie with UI in some way.
TDD is trivially easy to fake. Perhaps worse, it's trivially easy to think you're doing it, when you're actually doing nothing constructive.
In any kind of setting with shared code, it shouldn't be a matter of self-discipline, it should be a matter of standards and best practice. You shouldn't be integrating any code without test coverage. This is a standard part of how many projects handle pull requests.
If you're only accountable to yourself and writing the tests first is the technique that works for you, I can't criticize but you really don't have much to say to programmers in general, either.
While not, NOT a TDD approach, it did lead to a much higher code coverage and added a safety net when I had to change it: I knew I could change the code, and if the result was materially affected, I'd know.
It did slow me down in the initial writing, but in the revisions, it sped me up, IMO.
Seriously, the current status quo most of us live in right now is zero to very few automated tests. That's what I'm arguing against.
I do not claim trascendence. It's just what worked for me. I've never done TDD at any time in my life. Note, after reading the arguments for it here, I think I will give it a spin.
One thing I noticed though, is that if you don't write tests before hand, you don't have time to write them later. Your code tends to be harder to test too, so you never really write them (costs too much).
To me, it's not just about writing tests though. It's about writing an executable todo-list of your features.
Before TDD/BDD, I used to take the time to figure out everything I had to do with their relationships together. Most of the time, it would change during the implementation as I forgot about something important while "designing". Also, I used to implement 2/3 things together because they were related.
Now I only create a new test and make it pass, then I refactor if I need to and proceed to the next one. If a new idea comes up I write it down on a piece of paper for a future test.
This way, my Work In Progress is always 1, before that it was around 3/4 maybe. The mental overhead is much lower because I can rely on all the other tests I made to ensure I did not break my feature.
I'm not advocating pure reliance on TDD, but for 95% of the average developers out there, this is definitely an upgrade.