Numbers don’t lie; they just arrive and spill the truth. In 2010, Billboard named Nickelback the band of the first decade of the millennium, based on album sales and concert grosses. Less than five years later, the numbers tell a different story. Monday night, Nickelback headlined a show at the Sprint Center, an arena the band is accustomed to filling. But this time, instead of drawing a crowd in excess of 16,000, as it has in the past, Nickelback drew about 7,000