EA's big mobile games are losing ground to Kim Kardashian, Hearthstone, and King's Bubble Witch

Homer Simpson is not quite keeping up with the Kardashians.

Electronic Arts is watching as its biggest (but aging) mobile games are starting to wane in popularity. Publishers like Glu, King, and Blizzard, on the other hand, are all seeing their recent releases climb the mobile charts. This is an example of the difficult and competitive mobile-gaming landscape that can prove a challenge even for the biggest game makers. With an estimated $20 billion in consumer spending on smartphone and tablet apps on the line in 2014, few publishers are willing to sit it out.