I work in this field and when we say "social" games, we really mean flash-based facebook-hosted games. The games you mentioned, while they do have social components, are classified as "mobile" games. The former is dying quickly, and will completely die out, it's just a matter of time. The latter is still going strong, growing even. Which is why Zynga (and every other social game company) is focusing mostly on "mobile" right now.