I think, if the box office doesnt pick up much, that will be Fox's direction to whoever directs the next film. "Move the franchise back to what people expect from a POTA film. An earth far in the future that is entirely controlled by evolved apes. Humans as slaves. No human civilization left." Because most likely Fox is thinking that people are bored with what Matt is doing which is sticking close to contemporary times when humans are still fighting and the apes are just beginning and barely talking.
And frankly I wouldnt be opposed to that as long as the director does something good. As much as I love Caesar, I am ready to move way beyond the time period in Reeves films. Its time to start considering doing a remake/reinvention of the original film.
If that fails then Fox will likely shelve the franchise for a while.