A lot of bad sequels make orders of magnitude more money than critically acclaimed films, but the films that make the most money are rarely bad. The highest grossing films of the last three years have been Avatar, The Dark Knight, and Toy Story 3, which were all critical darlings to various degrees. People really want great movies but are willing to settle for mediocre ones that have some of the things they're looking for (e.g., exceptional visuals, or characters in which they're already invested).