I'm curious how much this is the cause or effect, though?

The publishers have been saying that their ability to promote books has drastically reduced with the internet, along with changes in reading and information habits.

It seems like a book needs a far bigger push today to rise above the noise of the internet (and people's over-abundance of content to consume), and this unfortunately meant that small publishers struggled unless they "joined together" to make a bigger push.

There's extremely small (self published) books and extremely large hits, but the middle is increasingly less viable, it seems. Similar to films.