So... what's the proof? The fact that you prefer them? Because that's not how opinions work. I wouldn't argue that the classic trilogy and, let's call them the "good" boost trilogy (Unleashed/Colors/Generations) differ greatly in their gameplay design. But it's very much subjective whether that matters. I personally find either trilogy to appeal to me in similar measures, and because either style meets my expectations of what I want out of a Sonic game, they scratch the same itch. They feature high-speed platforming spectacle, a focus on skill mastery, and a well of replayability and depth so deep that I never burn out on them. I've kept all six of those titles in regular rotation ever since I first played them. You might not see the boost games the way I do. They don't scratch that itch for you. That's okay. But my experience doesn't invalidate yours, and I would never try to argue it should. Whatever our opinions are, they don't constitute "objective proof" of anything except which video games we, as individuals, find more enjoyable.