Why would multiple authors make a difference?

Every time an article is created, saved or published, wp uses hundreds of non-cachable queries.

Every time an article is published, it causes the cache to be deleted for not only that article but related pages, which means all those pages have to be rendered again.

For one author, that can be managed. Many authors, the cache is constantly being defeated.

What matters is the ratio of reads per write. Blogs with multiple authors have a higher ratio than blogs with single authors.

>For one author, that can be managed. Many authors, the cache is constantly being defeated.

That's irrelevant. It's the pages view count that counts, not how many authors are in the same cms.