s0nicfan posted...
Mostly because, at the very core, Sonic was a tech demo for the Genesis that took off well beyond anyone's expectations. The original gimmick was "look how our guy can move so fast the other console can't even render it." 3D platforming is a lot easier when you're dealing with a short, squat plumber whose signature 3d moves are mostly standing jumps and short dives. You can design an entire mario level that takes 5 minutes to traverse and Sonic would blast through that in seconds. The result is you either railroad players into what are basically QTE segments, you make most of the game playing other, slower characters, or you make gigantic empty worlds that the player blurs past, and neither are particularly fun.
Sega has just never figured out exactly what they would need to do to make a full length 3D sonic game that mostly features Sonic actually fun. Some of it might be a lack of talent, but honestly I don't think it's unfair to say that after literal decades of the trying, it might just be that "go fast, the game" fundamentally doesn't translate to 3D outside of racing games.
I honestly want to see Nintendo try their hand at 3D Sonic. Let them make the game, and let Sega handle the aesthetics and especially music.