Sales are not indicative of quality. It's true for films just as much as videogames.
While true as LoD said...
These people are definitely in the business for money making, not kind words. But they definitely want to make a profit moreover be concerned if everyone loved the movie.
In the movie 'business' a badly reviewed movie with good sales & that makes a profit is usually more likely to get a sequel than a well reviewed movie with poor sales that has made a loss. Unfortunately its usually sales not quality that determine the overall success of a movie in the eyes of the movie executives.
Sharknado didnt get 6 movies based on its reviews or oscar worthy performances.