Especially in the early rounds.
In the end, the best couple usually wins or finishes a close second. In the past five years, there's probably been one, or possibly two, instances in which a couple that could have finished first got knocked out within the first four weeks.
The "popularity" contest aspect of it makes it a prime time broadcast TV show. If it was truly a dance contest, it would be on PBS and targeting just that niche audience that knows the dancers and their backgrounds -- thus, low viewership and no ad support.