The Divergent films, starring Shailene Woodley and Ansel Elgort, never quite turned the world on the way other YA adaptations like Twilight and The Hunger Games did. And when I say didn't didn't turn the world on I mean that the final film in the series, Ascendent, is going to skip movie theaters and just become a TV movie. Yes, this movie series is going to finish up on TV.
It's unclear if the actors will come along; there's no way the budget (which wouldn't have been big anyway) will stay the same on the small screen. And it's not certain that Woodley et al's contracts cover a TV movie. If the actors don't come it would make this finale feel like even more of a fizzle; if they do come along it would make the actors, who are trying to be rising stars, look small.
The plan is that once the finale movie airs the studio would go forward with a series set in the same post-apocalyptic world. As the CW proves you don't need big ratings to be successful on TV; numbers that caused this franchise to get kicked out of the cinema could be pretty reasonable for TV. And the price tag of the TV movie would be rolled into the cost of creating the show in the first place.
I am pretty certain that this has never before happened; part of the problem that Lionsgate is facing with this movie is that it's a phony entry in the series. The studio cut the third book, Allegient, in half... but the first half movie only made about 66 million bucks, a total failure. Now they're stuck with this unfinished series, and leaving it unfinished could hurt their aftermarket (Blu, streaming) sales.
I'm not sure if this is a referendum on YA adaptations, but it definitely is an eye-opener for people making movies where they assume there will 100% be a sequel. Maybe it's time to get back to treating each film as its own thing, rather than getting crazy confident.