You can achieve the same result with PHP and FTP, however once you start adding unit tests and branching, that's when things start to take time.
Long builds aren't necessarily a problem if they give you enough in return.
The reason we stopped doing that is because we wanted version control, we wanted to work in teams and we wanted unit and integration tests, which I doubt that you could run within 50ms.
> the feature flags, function versioning
I can easily replicate that with at least early 2000s PHP(would probably work with 90s PHP as well).
> DB migrations
We do have DB migrations in all web frameworks that are worth using.
A good way of thinking about Dark is to suppose that instead of stopping doing that, we found a way to make it work.
> I can easily replicate that with at least early 2000s PHP(would probably work with 90s PHP as well).
If you could replicate it, you'd do it. Except you need version control, unit tests, etc, etc. So you need tooling that has those things to make the feature flags work.
You found a way to run multiple selenium tests in less than 50ms?
Tests wouldn't be Selenium, and Dark can probably deduce which tests are affected by a particular code change (if it's close to purely functional/no side effects), so it does not need all of them ran.
I generally like the idea and approach technically, but wouldn't be using them because of lock-in nature.
I also worry about feature flags: for longer lived "features" (they happen!), code ends up being more complex and hard to maintain, and when the time finally comes to drop them, it's a mess.