Before their stupefying collapse on Sunday at Arrowhead Stadium, an era-defining moment was in the Chiefs’ grasp. Just waiting to be seized, even. Playing in their NFL-record fourth straight home conference championship game, they had swamped Cincinnati 21-3 in the first half and were on the verge of becoming just the fourth franchise to play in three (or more) straight Super Bowls. The rich subplots were all in place, too. Especially as the Chiefs were at the Cincinnati 1-yard-line on the final plays of the first half with a chance to administer a likely knockout blow before what dissolved in…
