> Most expats will rarely hear or need Dutch

That is an overstatement. Dutch is the primary language everywhere like the native language of any country. It is true that in major cities most people speak excellent English and you can definitely manage easily without speaking Dutch.

But Dutch is spoken absolutely everywhere and most signage is only in Dutch. Also, as soon as you get a bit outside of the big cities, you find many people with a middling level of English, similar to most other countries in Europe. Even in cities, many working class people and actually most immigrants from non English speaking countries only speak Dutch.