Reviews for both films have been mediocre, but still, box office drives business decisions, and when a sequel earns a little more than half of its predecessor, the idea of stretching the brand usually isn’t the best.
The most recent London Has Fallen made significantly less that the original, Olympus Has Fallen (where “Olympus” was the code name for the White House, which was attacked by vicious terrorists).
While we’re on the topic, who asked for another Something Has Fallen movie?