Refactoring a system built of microservices is slow and costly, according to the article; the recommendation follows from this. Why can't it be fast and easy? I

Refactoring a system built of microservices is slow and costly, according to the article; the recommendation follows from this. Why can't it be fast and easy? Is it essence or accident? (Like, do skilled Erlang programmers agree?) How does refactoring happen in the systems he's talking about?