The rivalry did not become so apparent until the Kansas City Athletics baseball team moved to Oakland, California in 1967. In 1969, the Kansas City Royals expansion team was placed in the same division as the Athletics. The 1966 Chiefs team participated in the first AFL-NFL World Championship Game, later known as the Super Bowl. The Chiefs and Raiders both had identical 12-2 records in 1968 and faced off in a playoff game to decide who would go to face the New York Jets for the AFL Championship. The Raiders won 41-6.
Yes, snapcount percentage played a role in the Raider's loss to the Chiefs. A higher snapcount percentage typically results in a more efficient and productive offense. The Chiefs' offense was expedient and was able to score more, and the snapcount percentage was a factor in the offense's success. The Chiefs were able to catch the Raider's defense off-guard and could be more productive in their possessions of the ball.
I don't think the player snapcount percentage made any difference. The Chiefs are a better team than the Raiders. If they played 100 times, I would expect the outcome to be the same the majority of the time. To blame the loss on snapcount percentage is an excuse. The Chiefs are the better team.
I'm not sure I know what any of this means. I think if the Raiders lost, then it was their playing that caused the lost. I'm unclear of what a snapcount is but I do not believe it would have an affect on the teams ability to play. Usually team work and skill causes the outcome of that.