Imagine you're playing Russian Roulette. 6 chambers one bullet. One way to play is to spin the cylinder after every turn. This makes every turn a 1 in 6 chance of "winning" and you could theoretically continue having turns forever without a winner. This is how wheel works.
Another way to play is to not spin the cylinder after every turn. This guarantees there will be a "winner" within 6 shots. This is how people wish wheel worked.