Manti could have went anywhere in the country for football, and he prayed, traveled, and chose ND for all of the right reasons. IDK what offers Tommy had, but I'd bet money ND was a no-brainer for him, as he probably didn't have a better offer on the table. Given Manti's almost guaranteed NFL future, you could argue ND was not his best option (although I wouldn't because you never know), but he still chose us for the religion, feel, tradition, and academics.
Like Senoj13 said, Manti is a once in a decade type of talent. Tommy is 5th on the passing list, correct. But don't confuse records with talent. Look at offenses no-a-days compared to when Montana played. It's a different type of football. Add to that that Tommy's had a ton of PT because of really, really unfortunate QB situations at ND.
Manti was the face of this program and the unquestioned leader of the team as a linebacker. What team has ever played in the title game and has been able to say that? Or any defender for that matter? Charles Woodson, maybe? The fact that he was held in such high regard by his peers tells me all I need to know about his leadership and character.
Side note - Manti graduated with ~3.2 which is very respectable for a football player at ND IMO. No idea how Tommy did academically? I'd guess fine, but not sure.
And if you read/hear what people outside of ND say about Manti, it's powerful, powerful stuff. He's not your typical student/football star. There's something special about him. It's like the Court's definition of pornography. You don't know how to define it, but you know it when you see it (sorry for the 180-comparison, it's all I had).
Tommy did well and ND is better for having him, but let's keep him in his lane.