> The dynamic world lets us have inconsistent code that partially works, rather than forcing us to follow up on all the places reached by the ripple effect of a change. Maybe the change turns out to be a bad idea in the end; then it was a waste of effort.

Except you can mostly do this reasoning just using the types. So you're rarely updating everything, you're just updating a few type definitions to see if your idea meshes well, and then you have to do the large refactoring.