“Didn’t Vanellope go Turbo?”
While yes, technically, what Vanellope did would be considered “Going Turbo” (game jumping for the sake of staying), there’s a distinct difference between what Turbo did and what Vanellope did.
Turbo was the only character you could play as in Turbo Time. He wasn’t just the main character, he was the only playable character, and in leaving his game he effectively removed a main game function from that world. And when he joined RoadBlasters, he didn’t try to blend in whatsoever. Hell, he even said his own catchphrase while on screen. He interrupted the main gameplay, drew attention to who he really was, and caused distractions and disturbances in RoadBlasters in a way that led players to believe the game was totally busted.
All in all, even if just for the fact that Turbo was the only playable racer in his game, without making a copy of himself it would have been impossible for Turbo to “Go Turbo” and permanently game jump with it going unnoticed. It never would have worked.
Meanwhile, Vanellope is one of a full roster of playable racer characters in Sugar Rush, a roster that randomizes at the beginning of every day. She may be featured on the outside of the arcade cabinet, but she went for ages living in hiding under “King Candy’s” (Turbo’s) rule without ever appearing on the roster, and without any players even noticing her absence. She could leave with everyone on the outside being none the wiser.
Plus, Vanellope chose to join Slaughter Race, an online multiplayer game with a massive cast of strange characters, each with totally unique appearances and designs. And her goal isn’t to stand out, like Turbo, her goal is to blend in and find a place she belongs. Even without much design tweaking, Vanellope could blend in there without much issue, and even if someone noticed that she looked like a character from ‘that one candy kart racing game I used to play at the arcade, huh, I wonder what she’s doing here’, nowadays people would assume it was an Easter Egg. It IS the age of the Internet, after all.
So long story short, it’s less about the fact that Vanellope and Turbo both game jumped, it’s more about their goals behind doing so, and also how much their meddling actually affects the games that they are leaving and joining. If Turbo had managed to clone himself to keep Turbo Time running, or if he somehow managed to incorporate himself more fully into the gameplay of RoadBlasters, “Going Turbo” wouldn’t even be a known phrase in the arcade because neither game would have gotten unplugged. But since Turbo was just an attention-seeker who wanted all the glory of being the “greatest racer ever”, his obsession with being in the spotlight screwed over both his game and the one he had hoped to take over.