This. I'd like to give you 100 upvotes if I could. Add to this, even the same user doesn't want use the same 20% of the all the time. Tastes change, preferences change, new apps come out.

What @dhh's argument reduces to, is that the long tail doesn't matter. But only, it really does. But as you say, the long tail is what makes it a great UX for users.