Again there you go hand picking examples. Everybody wants to throw Ryan Leaf's name out there without actually looking at what hapened to him. Yes Ryan Leaf did have very high talent and potential. It wasn't a lack of physical skills that kept him from being a good to great QB. It was all his mental skills or lack there of. He all of a sudden couldn't throw the ball 50 yards anymore, he didn't get weaker, or any of that other foolishness. He didn't succeed in the NFL because he didn't know how to use his talents properly and along with the mental issues he had.
There is a reason why players are drafted in the first round and players are drafted in the sixth round. Guess what that is?? That's right it potential. Everybody and thier momma knew Calvin Johnson and Adrian Peterson had the physical talents and potential to be great stars in the NFL and guess what they have. Reggie Ball didn't have that potential to be an NFL QB and guess what he is not.
So yes where a player is drafted makes a huge difference. Anybody can call out some late round pick who became a star but if you look at all the guys drafted around them they suck. There always a guy or two that exceeds the odds but
FAR more times than not that sixth round guy doesn't stay around very long if he stays around at all.
To help you understand the point then I will do you one better. You can make a top 10,15, 20 or whatever list for any position in football or basketball or whatever and I promise you that the vast majority of those guys will be early draft picks.
Just for kicks let's use the WR position as an example. Most if not all people will say the top WR's in the league today are Fitz, Andre Johnson, Moss, Calvin Johnson, Steve Smith, Reggie Wayne, Roddy White, Greg Jennings, T.O, and Boldin. Out of those 10 players
SIX of them was drafted in the first round, 2 in the second round, and the other two in the third round. The two that was drafted in the third round came from small schools and where not really known out of college but thier skills still got them drafted in the first day. See the point??