Question

Suppose there is an election for Soft Drink Commissioner. The field consists of one candidate from the Pepsi party and four from the Coca-Cola party. This would seem to indicate a strong preference for Coca-Cola among the voting population, but the Pepsi candidate ends up winning in a landslide. Why does this happen?

Short answer

The Pepsi candidate ends up winning despite Coca-Cola having a strong preference because votes from the Coca-Cola population were split between 4 candidates. This resulted in a Pepsi candidate winning the election despite being unpopular.

Step-by-step solution

Step 1. The winner take all voting system

This problem explains the flaws in a winner take all voting system, where multiple candidates of the same field weigh each other down, this happened to coca-cola. Whereas Pepsi voters have no choice and must vote for the same person, however, they may not be as happy with that single choice.
If there are 3000 coca-cola votes split evenly between candidates, they will still lose to only 1000 Pepsi voters.
This outcome results in less choice, as only running one candidate is more likely to win.

Step 2. Real-world applications

This example is a metaphor for United States government elections.
Coca-Cola having 4 candidates represents the diverse values and opinions in a population, each voter likely feeling more strongly for their candidate than if they only had one choice.
On the opposite, Pepsi voters may not all be happy with only one choice to vote for, but they all prefer to vote for Pepsi than coke, so all their votes are consolidated to one candidate.
This is part of the reason why American electoral candidates are so unpopular because middle-of-the-road candidates have to cover a wide swath of voters.
Alternative voting systems can handle multiple candidates without diluting voting power, this occurs in a ranked-choice voting system.