Right now, their big sellers are Bruce Springsteen's autobiography (which I liked!), Amy Schumer's autobiography, and A Man Called Ove. They are doing fine, as publishing companies go.
But they may have signed their death warrant with this purchase: $250K to Breitbart Nazi Milo Yiannopoulos. Publishers have signed villains before, but I can't remember any who have received this reaction from a major review of books:
In response to this disgusting validation of hate, we will not cover a single Simon & Schuster book in 2017. —Chicago Review of Books