I worked in publishing for a short while on the tech side of things and had this same question. It turns out print is very similar to other forms of media, in t

I worked in publishing for a short while on the tech side of things and had this same question. It turns out print is very similar to other forms of media, in that it's power law distributed, possibly even more extreme than video or audio. The VAST majority of books written never sell any appreciable number of copies. And a few books/authors sell millions. So there is intense competition to become the PR and distribution machine for those winners (or manufacturer winners based on guesses of what might be trendy/popular). You can self publish only up to a certain point. If your book is truly popular, or you want it to become so, or you want to make real money, there is no way to "self print" millions of copies and distribute them, feature them on Amazon, etc. That's literally why the publishing company exists. "Sharing ideas" is completely orthogonal to the point of large publishers. Relevant to this suit, large conglomerates like PRH actually operate as many independent publishing houses (most of which have been acquired over time). They each have their own brands and editorial staff and want to show good results. This leads to intra-company bidding for the same books, which is obviously good for authors but bad for the company. So this merger would just make that effect more extreme. Probably the DOJ scrutiny is warranted here.