Tennis - where are all the young guns??

Tennis needs them, badly... The top has been the same for too long - Fed, Nadal, Andy, Joker, Ferrer, Soderling, etc. Now, OLDER who have been in the game for quite some time are hitting the top ten and cracking the top 15 - Monfils, Meltzer, FIsh, Andy, Youszney, etc... Where are the YOUNG GUNS - 18 - 20 year olds who strom the scene the way Becker, Sampras, Agassi, Chang, Edberg, Lendyl, Mac did... It seems you see all the same names every tournament... I like Raonic alot - big serve and big groundies, and I thought Tsonga had a chance to win a major, but tennis is lacking in young guns wgo can challenge Nadal, Fed and Joker . . . Perhaps the game is not developing players as it used to or the current wave of players is just not that good. Ryan Harrison, a current young US player on the rise as most say, is only 5'8" and in my opinon just does not have the size nor the power to really ever make a dent in the top players. Grigor Dmitrov, the next FED some said, is hovering around the 80 mark and has yet to do ANYTHING in big tourneys... Where are you guys? Are you hiding? Are you scared and waiting for Nadal and Doker to get older? Are you guys not ready for the stage? I mean, lets go youngsters, show some guys, some sweat, some tears, some toughness and show tennis that you young guys have a heartbeat. Tennis needs you!!!