RPGFan has published a short editorial that analyzes the growing trend of role-playing elements being injected into other genres, and vice versa.
My personal theory is that the term "RPG" can no longer apply to a definable genre in the regular sense of the word. The word now encompasses a multi-faceted idea which has extensions into other genre, borrowing and lending as necessary. Where Mass Effect was loaned statistics and dialogue trees, it also borrowed first-person shooting and action game aesthetics. Where Devil Summoner 2: Raidou vs. King Abbanon was loaned exploration and menu-based interfaces, it borrowed detective work and graphic adventure tropes.
As the industry develops, creators are finding more and more ways to integrate disparate ideas within an RPG. The core tenants of the RPG have always been giving the player control over exploration, guiding them through segments in a lengthy story, and exuding an atmosphere of bookishness.
In short, they have to be character-driven adventures where the players keep track of numbers.