Disney, Dreamworks and others have looked at the American and worldwide box offices determined 2d, "cel" animated features just don't appeal enough to today's audiences to give the return on investment their stockholders desire. Traditional stop-motion studio Laika (Coraline, Boxtrolls, Paranorman, Kudo and the Two Strings) has committed to a 2d feature in the future.
There are still 2d animated features coming out, mostly from Europe and Asia. This decade, theaters have seen Winnie the Pooh (yes, Disney did one in 2011, relying mostly on overseas service studios), Song of the Sea, The Breadwinner (current Oscar nominee), Long Way North, Ernest and Celestine (my fav), A Cat in Paris, The Red Turtle, Arrietty, The Wind Rises, In This Corner of the World, countless other anime, and even My Little Pony: The Movie.
Mary Poppins is not only using 2d animation, I've had friends in the industry hint that they aren't relying on the computer ink and paint Disney has used for 25 years now. There are camera checkers working, which usually means they are using real cels.