But we state that one clicked with audiences and the other didn't, yet they pulled in roughly the same cash. So this wasn't about audiences rejecting the film, it was about Hollywood excess.
That's true to a degree, although some films need huge budgets to tell stories on a grand scale. The bigger the budget the more widely a film needs to click with audiences.
If box office returns were the only requirements for a sequel we'd have seen a third Fantastic Four movie years ago.
made 3.3X its production budget, a very strong return and a level that almost always sees a direct sequel made very quickly. Fantastic Four 2
made 2.2X its production budget, a mediocre return (given the split in box office between the studio and the theatres) that puts a film in a grey area where a sequel may or may not be made. In this case it wasn't made, with the studio opting for a reboot after the passage of some years instead.