Now it explains why the movie took so long that is because the 6 years was spent to make all of the animatronics (2:06 and there are 6 animatronics Chicha, Freddy, Foxy, Cupcake, Bonnie, SpringTrap) and then 2 years to film the whole movie. Yeah that really explains why it took 8 years to make that film.
Actually, it took 7 years to find the right studio and about a year and a half of making the film. Scott rejected over a dozen potential scripts to find the right one