MSU never out recruits the other schools and never pulls in top 10 classes, according to the amateurs that do these rankings. Yet they've beaten UM 7 of the past 8 years, and also does really well against Ohio State, Penn State, and the rest of the league too.
So its good coaching, I agree. But its not JUST great player development, which everyone seems to assume. You can't develop untalented players and turn them into stars.
MSU has identified talent that others didn't recognize. Narduzzi is part of that. Several reporters have mentioned that they've never seen a coach care less about what others think of his recruits than Narduzzi; he believes in his abilities to assess talent, and could care less about rankings, other offers, etc. And he has a successful track record to back that confidence up.