Honestly, I'm pretty sure that you could take the RB's and DB's at some place like USC, coach them for a year and they'd probably make the final 4.
All i know is that in a year and a half, my brother went from never playing the sport and getting cut from his middle school team to starting on the varsity, making the top summer travel team in NJ and getting letters from D1 schools (including the Ivy's). If he can do that, after being very mediocre at every other sport he tried, i gotta think a 5'11 200 lb RB that runs a 4.4 would catch on pretty quick.
No doubt that great athletes can become very good lacrosse players. Great athletes can usually become very good at most sports with coaching and dedication.Your statement may have been intended as hyperbole. I hope so, because the idea that you could take a bunch of great athletes and introduce them to a completely new sport and have them be competitive with the top D-I programs in a year is just ludicrous.
As for your statement about the level of pure athlete that plays the sport at the college level, there is
some truth to it. The average D-I lacrosse player isn't going to be comparable to a DB or RB at a major college football program in terms of size/strength or explosiveness. But as the sport grows in popularity nationally there are more and more truly athletic kids playing the game. A few are true athletic freaks.
Look at Virginia. The Bratton brothers are both elite athletes. Both Syracuse and Virginia have had players who turned down D-I football scholarships to play lacrosse over the last several years as well.
Or take a look at a guy like Paul Rabil, who was an AA at JHU a couple years back. He is 6'3" 225 pounds and is one of the fastest guys on the field. He has great feet and quickness. He can also shoot the ball 110 mph. And can shoot accurately, with either hand, while on the run. Could he play in the NFL? No. But he could have been a good LB or WR in college. Maybe not a top player at a BCS school, but he definitely has the athletic ability to have been a productive D-I football player.