I wouldn't say it's lazy, but it is low risk high reward. If you make a movie of an already popular thing, people who like the popular thing will go watch it.

I wouldn't say it's lazy, but it is low risk high reward. If you make a movie of an already popular thing, people who like the popular thing will go watch it. Making a sequel of that thing means only the people who watched [AND LIKED] the first thing will watch the second one, also ensuring top tier ratings, making more people want to see what makes it so great. Having original movies is a true blessing; but sequels, remakes, novel and comic book movies are true "office box smashes" with very, very little to risk.