Thanks for the reply! I can see your way of thinking, but the concept of navigating by directory seems to be a very dated way of thinking.
I don't intend to have, say "publisher.com/food/" landing pages—the navigation menu will point users to any appropriate archive views. On a site that did have those landing pages live, I can see that a few users might want to find their way around via subdirectory. But I think virtually all web users navigate by click, not by URL, especially on mobile.
There will be a central "feed" that links to all content, and this feed will be paginated back to the beginning of all posts. I believe this is sufficient for Googlebot, no? Setting aside any UI / nav issues, is there a structural reason to keep subdirs in a URL?