No, it's not just all about GM Jerry Reese being bad at drafting players. It's a lot more complicated than that.
By whatever statistical measure you choose , the New York Giants have not gotten enough production from their last half-dozen draft classes. The Giants have one player, Jason Pierre-Paul, left from their 2010 NFL draft class. They have zero players left from either their 2011 or 2012 draft classes. They have four players but only two regulars -- Justin Pugh and Johnathan Hankins -- from the 2013 class.