Stars Wars movies are worth a lot and may be what Harrison Ford earns is little compared to the revenue generates from the movies. The movies have been received well by all ages, and if they can afford to pay such kind of money it means it is economic viable.
The original Star Wars movies were very creative but did not have a loyal audience at the beginning. Now, decades later, the fans are willing to pay for movies tickets and buy high priced merchandise because there is top recognition from the branding of the Star Wars name. The high salaries for the actors are also justified, as Harrison Ford is a proven talent now.
If the new Star Wars movies weren't making money at the box office then it would be reasonable to say that the cost would be completely unjustifiable. However, given the continued popularity of the franchise and the fact that the films are continuing to make a significant profit then it is reasonable to allow the production company to carry on as they are doing.
In every community all over the United States, fans young and old line up to watch Star Wars. Even though the first Star Wars movies were made in the 1970s, they are popular among people who were not even born when they were made. The Disney company makes a lot of money off these films.