Agreed, but the article begins with the previous quote, and is entitled "what functional programmers get wrong", so I feel like there's some preliminary assumptions being made about FP that warrant examining.

In practice, much of the article seems to be about the problems introduced by rigid typing. Your quote, for instance, is used in the context of reading old logs using a typed schema if that schema changes. But that's a non-issue in the FP languages mentioned above since they tend towards the use of unstructured data (maps, lists) and lambdas. Conversely, reading state from old, schema-incompatible logs might be an issue in something like Java or C++, which certainly are not FP languages as the term is usually understood.

So overall, not really an FP issue at all, and yet the article is called "what functional programmers get wrong". The author's points might be very valid for his version of FP, but his version of FP seems to be 'FP in the ML tradition, with types so rigid you might want to consult a doctor after four hours'.