The Cowboys didn't luck out on Prescott. They met with him at the Senior Bowl, coached the South against his North team, of which he was the MVP of the game. They also sent scouts/coaches to his workouts, twice I believe.
There were very few of us who were high on this pick on draft day. I kept telling people Dak has that "it" factor, the first I've seen since Romo. Most people were ticked off because we didn't trade for Lynch, but it was reported that even had we gotten Lynch, we still wanted Prescott if he dropped low enough. When we didn't get Lynch, they wanted Prescott even more.
This was not luck .. the Cowboys coaches and scouts were all high on Dak. I told people when we didn't make the trade for Lynch, we likely lucked out. I fully expected the Cowboys to draft Dak assuming another team didn't grab him too high. Once we got him, I said people would be surprised by his ability to play.
That said, as much as I expected of him, I did not expect this much, this soon.