Just look at the physiques of our lineman now compared to the 90's lineman. No contest. I started this thread because I am an old guy, 52, who powerlifted for a lot of years at the "hard core" gyms and I feel strength and conditioning has become way too complicated and over analyzed. True strength comes from the 3 basic lifts; bench, squat, and deadlifts. If done properly with the right percentages of the 1 rep max, a young athlete can become a force. Sure a flashy vertical leap or agility test is great and has it's place but, one on one, the stronger guy will win the battle in blocking and tackling when it comes down to it (of course it helps to have the fire burning in your heart too).
I think true strength training has been corrupted because it has now become big business and everyone has to have the latest new technology etc.