> Let's say you want to write a function that can capitalize all the string fields in the object passed in. In a dynamic language, you could map over the values and apply capitalization trivially. It would be a one-liner.

That's fair, but can you explain the context here? I.e. why are we trying to capitalize all the field names of a record object? This may be an 'XY' problem--you may be trying to accomplish some final goal and 'capitalize all the field names of a map' seems like an obvious intermediate step to you, while to a statically typed language programmer they may take a very different approach.