Even if studios were willing to roll the dice on a budget-heavy two-part film project, there are a whole lot of projects out there that fit the mold established by those movies that were successful in such an effort.
J.K. Rowling's Fantastic Beasts and Where to Find Them, for example, isn't fully based on an underlying book, so any sequels that come along, however unplanned, are still just plain old sequels and not extensions of a single installment. Meanwhile, Fifty Shades of Grey, which seems like the best guess for a fellow in the two-part finale trend, just didn't have a sophomore smash at the box office the way Twilight and The Hunger Games did to justify turning its final story into two films.
While Stephen King's It may be hefty enough for even three films in total, New Line Cinema hasn't indicated any interest in that possibility but has set the date for the pre-planned Chapter Two for 2019, as expected. Yes, it's a two-parter but not in the same sense as Deathly Hallows, Breaking Dawn, and Mockingjay were. Nevertheless, it's the closest thing to continuing the two-part film trend out there right now.