The big boys are generally profitable, overall.
About 11% margin worth of profits.
(Smaller publishers... it varies. Which is why the big boys keep finding acquisition targets.)
http://www.digitalbookworld.com/2014...actually-make/
On the other hand, if you look at their profits, most of it comes from ebooks, which account for 20%-plus of their revenues.
http://www.digitalbookworld.com/2014...big-publisher/
Depending on how you interpret the public data you could make a case that pbook publishing is a money loser.