Yes. And all equally true for statically typed languages.
Refactoring without tests is easier in a statically typed language, but still stupid. If you assume a decent body of tests, the benefit dissipates quickly.
If you prototype faster, as you usually will in a dynamically typed language, your design mistakes cost less. Since in large software systems I tend to find that the two biggest sources of bugs are a) errors in specification and b) poorly designed APIs, not obscure edge case bugs, quicker prototyping helps in large projects too.
And, if your design is solid, you can still achieve similar benefits as static typing by "locking down" your boundary code with asserts so that future development that interacts with that boundary code will fail quickly if it interacted with in the wrong way.
>At that point, you're not limited by your typing speed as you may be putting in net 10 lines of code a day. There is just no benefit to dynamic typing at that point.
This is fallacious. You're never limited by your typing speed in any language at any point. The cost of "extra typing" is cognitive, not a finger speed limitation.
The benefit of dynamic typing is more flexibility in the code you write (especially useful for writing frameworks and such) and quicker turnaround when prototyping because you do not have to prespecify as much up front.
