Opinionated Apple seems to get away with it.

Well, I'm not familiar with their office suite, but I bet that, if I open their word processor, I will still find a ton of features that I will never use.

The question is more if they left out features because they were deemed too difficult for the average user.

In the context of this blog post, yes. But in the broader context of the quote, a word processor having a ton of features shows that you don't really get away with only implementing 20% of the functionalities.