What Happened to Kansas Football?

After going 12-1 in 2007 under Mark Mangino, Kansas football has been on a downwards trend for a long time. Since Mangino left the program after 2009, the Jayhawks have won a total of 18 games in 9 seasons. Nobody expected Kansas to be a major threat, but no one could've predicted a run like this. So how exactly did it happen?