One thing to keep in mind is WWE jobbers might still be paid better than headliners for ROH/TNA/NJPW so that could be why they stay. They could be hoping to be tapped if one of the main guys gets injured, or if they need a fresh villain.
I still think the ultimate Zack Ryder is still to come. They did totally miss the boat with him, the time to build him was when Kane was trying to corrupt Cena by beating up Ryder, when Ryder was jealous of Eve Torres wanting Cena when Ryder liked Torres.
HeartBROKEN Ryder should've become Kane's apprentice (EMBRACE THE HATE) when Cena rejected him, revamped his image, gone full dark side, and Cena should've jobbed to Ryder to elevate him as a main event villain.
Ryder would be returning to his roots, he was Edge's flunky in La Familia after all. He could succeed Edge as the new ruthless heel just like Matt Taven succeeded Adam Cole in The Kingdom.